Acts 10:12
10 διελθόντες δὲ πρώτην φυλακὴν καὶ δευτέραν ἦλθαν ἐπὶ τὴν πύλην τὴν σιδηρᾶν τὴν φέρουσαν εἰς τὴν πόλιν, ἥτις αὐτομάτη ἠνοίγη αὐτοῖς καὶ ἐξελθόντες προῆλθον ῥύμην μίαν, καὶ εὐθέως ἀπέστη ὁ ἄγγελος ἀπʼ αὐτοῦ.
Rev. 15.5
Καὶ μετὰ ταῦτα εἶδον, καὶ ἠνοίγη ὁ ναὸς τῆς σκηνῆς τοῦ μαρτυρίου ἐν τῷ οὐρανῷ,
For starters, ἀνοίγω is a very irregular verb. The verb is from the preposition ἀνα and the verb οἴγω (which you never find by itself). So this verb may not be the best verb to try to get a more global understanding of how regular changes happen in passive aorist verbs. Some forms present three different forms, e.g. ἠνέῳξα vs. ἤνοιξα vs. ἀνέῳξα. I think one perfect form has 3 augments: ἠνέῳγμαι(?). Here are the BDAG, LSJ, and Smyth form entries.
There are second aorist passives which do not contain the -θ- morpheme. See Smyth:
554. a. The second aorist and the second perfect are usually formed only from primitive verbs (372), These tenses are formed by adding the personal endings (inclusive of the thematic or tense vowel) to the verb-stem without any consonant tense-suffix. Cp. ἔλιπο-ν with ἔλῡ-σ-α, ἐτράπ-ην with ἐτρέφ-θ-ην (τρέπω turn), γέ-γραφ-α with λέλυ-κ-α.
b. The second perfect and second aorist passive are historically older than the corresponding first perfect and first aorist.
c. τρέπω turn is the only verb that has three first aorists and three second aorists (596).
d. Very few have both the second aorist active and the second aorist passive. In cases where both occur, one form is rare, as ἔτυπον (once in poetry), ἐτύπην (τύπτω strike).
e. In the same voice both the first and the second aorist (or perfect) are rare, as ἔφθασα, ἔφθην (φθάνω anticipate). When both occur, the first aorist (or perfect) is often transitive, the second aorist (or perfect is intransitive (819); as ἔστησα I erected, i.e. made stand, ἔστην I stood. In Other cases one aorist is used in prose, the other in poetry: ἔπεισα, poet. ἔπιθον (πείθω persuade); or they occur in different dialects, as Attic ἐτάφην, Ionic ἐθάφθην (θάπτω bury); or one is much later than the other, as ἔλειψα, late for ἔλιπον.
Smyth, H. W. (1920). A Greek Grammar for Colleges (p. 175). New York; Cincinnati; Chicago; Boston; Atlanta: American Book Company.
And BDF:
76. First-second aorist and future passive. (1) New second aorists (passive): in the Hellenistic period the second aorist is very popular (more Ionic than Attic). Thus in the NT (apart from regular Attic forms): ἠγγέλην, ἡρπάγην (along with the Attic ἡρπάσθην), ἐκάην, ἐκρύβην, ἐνύγην, ἠνοίγην, ὠρύγην, ἐπάην (§78), ἐτάγην, ἐφράγην, ἐψύγην. But ἐκλίθην κλιθήσομαι (poetic) forms a first aorist following ἐκρίθην instead of the Attic ἐκλίνην. (2) An aorist passive in place of an intransitive active or middle: a new first aorist passive replaces an intransitive in ἐτέχθην Mt 2:2, Lk 2:11 (for Attic ἐγενόμην), and often ἀπεκτάνθην (for Attic ἀπέθανον); an intransitive root-aorist (ἔφυν ἔδυν) is being replaced by a second aorist passive built on the same stem in ἐφύην ἐδύην (cf. ἐρρύην). A. Prévot, L’aoriste grec en -θην (Paris, 1935) 178ff., especially 208–14.
(1) Ἠγγέλην (only in compounds) 1 P 1:12, Lk 8:20, R 9:17 OT, A 17:13 is probably not Att. (Lautensach 265f.).—Ἡρπάγην 2 C 12:2, 4, ἡρπάσθη Rev 12:5 p47ACP (-άγη S, -άχθη 046), ἁρπαγησόμεθα 1 Th 4:17.—Κατεκάη Rev 8:7, κατακαήσεται 1 C 3:15, (2 P 3:10), otherwise ἐκαύθην καυθήσομαι as in Att.; ἐκάην is Ionic (Homer, Hdt.); MGr has ἐκάηκα in addition to ἐκαύτηκα.—Ἐκρύβην Mt 5:14 etc.; cf. κρύβειν §73; these new second aorists prefer a voiced stop (as final stem-consonant) even though, as in this case (κρυφ-), it is not original (Att. -φθην, poet. -φην); Lautensach 251.—Κατενύγησαν A 2:37, cf. LXX (Thack. 237).—Ἠνοίγησαν Mk 7:35 (-οιχθ- p45 A al.), -γη A 12:10 (-χθη EHLP), Rev 11:19 (-χθη 046), ἀνοιγῶσιν Mt 20:33 (-χθ- CN al.), Rev 15:5, -γήσεται Mt 7:7, 8 (-γεται B), Lk 11:9 (-χθ- DEFG al.), 10 (-χθ- AEFG al., -γεται BD); in addition to ἀνεῴχθην, ἠνοίχθην and the like (§101); -χθ- is Att.; -γ- is found in the post-Christian pap. (Dieterich 211).—Διορυγῆναι (v.l. -χθῆναι) Mt 24:43, Lk 12:39, cf. ὠρύγη Herm Sim 9.6.7.—Διαταγείς G 3:19, ὑπετάγην R 8:20, 10:3, etc., ὑποταγήσομαι 1 C 15:28, H 12:9, (Barn 19.7); cf. προσετάγη Herm Man 4.1.10; but ποιεῖν τὰ διαταχθέντα Lk 17:9, 10 as in Att. (official language; cf. Jos., Ant. 5.252, 11.138, 20.46, Vit. 109).—Φραγῇ R 3:19, -γήσεται 2 C 11:10; LXX ἀπ- and ἐνεφράγη, ἀποφράγητε, ἐμφραχθείη, -θήσεται.—Ψυγήσεται Mt 24:12 (-χήσεται K; ἐψύχην is also class.); cf. above under ἐκρύβην (ψύγω is later; cf. Lobeck on Soph., Aj.3 p. 373 n.). Lautensach 233f.—Ἐκλίθην is also found in the LXX (Helb. 96); κλιθέντα PTebt 3.4 (epigram i BC).
(2) Ἐτέχθην and ἀπεκτάνθην are found also in the LXX (Helb. 96; Thack. 238). On ἐτέχθην also cf. Schmidt 463.5; Melcher 16; Lautensach 241.—Φυέν Lk 8:6, 8, συμφυεῖσαι 7, ἐκφυῇ Mt 24:32 = Mk 13:28; παρεισεδύησαν Jd 4 B. Cf. Reinhold 76; Helb. 96f.; Thack. 235; Schmidt 467 (Jos. ἔφυν and ἐφύην); Prévot, op. cit. 198; Mayser I2 2, 161. Ἐφύην AEM XIX 228.5, 11 (Michaïlov2 180).
Blass, F., Debrunner, A., & Funk, R. W. (1961). A Greek grammar of the New Testament and other early Christian literature (p. 41). Chicago: University of Chicago Press.
BDAG:
ἀνοίγω (ἀνά, οἴγω ‘open’; Hom. +) on this by-form of ἀνοίγνυμι see Kühner-Bl. II 496f; W-S. §12, 7 and §15 (p. 130); B-D-F §101; Rob. 1212f; Mayser 404. Fut. ἀνοίξω; 1 aor. ἀνέῳξα J 9:14 (vv.ll. ἠνέῳξα, ἤνοιξα), ἠνέῳξα vs. 17 (vv.ll. ἤνοιξα, ἀνέῳξα), mostly ἤνοιξα Ac 5:19; 9:40 al.; 2 pf. (intr.) ἀνέῳγα; pf. pass. ἀνέῳγμαι 2 Cor 2:12 (v.l. ἠνέῳγμαι), ptc. ἀνεῳγμένος (ἠνεῳγμένος 3 Km 8:52; ἠνοιγμένος Is 42:20), inf. ἀνεῴχθαι (Just., D. 123, 2). Pass.: 1 aor. ἠνεῴχθην Mt 3:16; v.l. 9:30; Jn 9:10; Ac 16:26 (vv.ll. ἀνεῴχθην, ἠνοίχθην); inf. ἀνεῳχθῆναι Lk 3:21 (ἀνοιχθῆναι D); 1 fut. ἀνοιχθήσομαι Lk 11:9f v.l.; 2 aor. ἠνοίγην Mk 7:35 (vv.ll. ἠνοίχθησαν, διηνοίγησαν, διηνοίχθησαν); Ac 12:10 (v.l. ἠνοίχθη); Hv 1, 1, 4 (Dssm. NB 17 [BS 189]); 2 fut. ἀνοιγήσομαι Mt 7:7; Lk 11:9f (v.l. ἀνοίγεται). The same circumstance prevails in LXX: Helbing 78f; 83ff; 95f; 102f. Thackeray 202ff.
Arndt, W., Danker, F. W., & Bauer, W. (2000). A Greek-English lexicon of the New Testament and other early Christian literature (3rd ed., p. 84). Chicago: University of Chicago Press.
LSJ
ἀνοίγνῡμι Lys.12.10; ἀνοίγω Pi.P.5.88, Hdt.3.37, 117, and Att. as IG1.32 (συν-), al.: later ἀνοιγνύω Demetr.Eloc.122, Paus.8.41.4: impf. ἀνέῳγον Il.16.221, al., Hdt.1.187, etc.; also ἀνῷγον Il.14.168; rarely ἤνοιγον X.HG1.1.2 and 6.21; Ion. and Ep. ἀναοίγεσκον Il.24.455; late ἀνεῴγνυον App.BC4.81, etc.: fut. ἀνοίξω Ar.Pax179: aor. ἀνέῳξα Id.V.768, Th.2.2, Hp.Vict.2.56, part. ἀνεῴξας CIG (add.)4300d (Antiphellus); also ἤνοιξα X.HG1.5.13 and in late Prose; Ion. ἄνοιξα Hdt.1.68 (best codd. ἀνῷξα), 4.143, 9.118; poet. ἀνῷξα Theoc.14.15, κἀνῷξε Phld.Acad.Ind.p.103 M.: pf. ἀνέῳχα D.42.30, Men.229; ἀνέῳγα Aristaenet.2.22 also intr. (v. infr.): plpf. ἀνεῴγει Pherecr.86 (Pors.):—Pass., ἀνοίγνῠμαι E.Ion923, Ar.Eq.1326: late fut. ἀνοιχθήσομαι LXXIs.60.11, Epict.Ench.33.13 (v.l.).; ἀνοιγήσομαι LXXNe.7.3, PMag.Par.1358; ἀνεῴξομαι X.HG5.1.14: pf. ἀνέῳγμαι E.Hipp.56, Th.2.4, etc.; ἀνῷγμαι Theoc.14.47; later ἤνοιγμαι (δι-) best reading in Hp.Epid.7.80, cf. J.Ap.2.9; plpf. ἀνέῳκτο X.HG5.1.14 (pf.2 ἀνέῳγα is used in pass. sense in Hp.Morb.4.39, Cord.7, and later Prose, as Plu.2.693d, Ev.Jo.1.51, 2Ep.Cor.6.11, Luc.Nav.4 (though he condemns it Soloec.8); but in Att., only Din.Fr.81): aor. ἀνεῴχθην E.Ion1563, subj. ἀνοιχθῇ D.44.37, opt. ἀνοιχθείην Pl.Phd.59d, part. ἀνοιχθείς Th.4.130, Pl.Smp.216d; later ἠνοίχθην Paus.2.35.7, LXXPs.105(106).17; and aor. 2 ἠνοίγην Ev.Marc.7.35, Luc.Am.14, etc.—In late Gr., very irreg. forms occur, ἠνέῳξα LXXGe.8.6; ἠνέωχα PMag.Par.1.2261; ἠνέῳγμαι Apoc.10.8, Hld.9.9; ἠνεῴχθην LXXGe.7.11; also aor. 1 inf. ἀνωίξαι Q.S.12.331; ἀνωίχθην Nonn.D.7.317:—open, of doors, etc., ἀναοίγεσκον μεγάλην κληῗδα they tried to put back the bolt so as to open [the door], Il.24.455, cf. 14.168; πύλας ἀνοῖξαι A.Ag.604; θύραν Ar.V.768; also without θύραν, ἐπειδὴ αὐτῷ ἀνέῳξέ τις Pl.Prt.310b, cf.314d; χηλοῦ δʼ ἀπὸ πῶμʼ ἀνέῳγε took off the cover and opened it, Il.16.221; φωριαμῶν ἐπιθήματα κάλʼ ἀνέῳγεν 24.228; so ἀ. σορόν, θήκας, Hdt.1.68, 187; κιβωτόν Lys.12.10; ἀ. σήμαντρα, σημεῖα, διαθήκην, open seals, etc., X.Lac.6.4, D.42.30, Plu.Caes.68; and metaph., καθαρὰν ἀνοίξαντι κλῇδα φρενῶν E.Med.660; ἀ. βίβλινον (sc. οἶνον) tap it, Theoc.14.15; γῆρυν ἀνοίξας, for στόμα, Tryph.477; ἀ. φιλήματα kiss with open mouth, Ach.Tat.37.
Liddell, H. G., Scott, R., Jones, H. S., & McKenzie, R. (1996). A Greek-English lexicon (p. 145). Oxford: Clarendon Press.
Smyth
ἀν-οίγ-νῡμι and ἀν-οίγω open: imperf. ἀν-ἐῳγον (431), ἀν-οίξω, ἀν-έῳξα, 1 perf. ἀν-έῳχα, 2 perf. ἀν-έῳγα (rare, 443) have opened, ἀν-έῳγμαι stand open, ἀν-εῴχθην, fut. perf. ἀν-εῴξομαι, ἀν-οικτέος. Cp. 808. οἴγνῡμι and οἴγω (q.v.) poetic. Imperf. ἀνῷγον Ξ 168 may be written ἀνέῳγον w. synizesis. ἤνοιγον and ἤνοιξα in Xen. are probably wrong; Hom. has ᾦξα (οἶξα?), and ὤειξα (MSS. ὤϊξα) from ὀείγω (Lesb.); Hdt. ἄνοιξα and ἀνῷξα (MSS.). (IV.)
Smyth, H. W. (1920). A Greek Grammar for Colleges (p. 687). New York; Cincinnati; Chicago; Boston; Atlanta: American Book Company.