οἶσιν’ γὰρ τῆς ψυχῆς ἐπὶ πᾶν πρᾶγμα, οἷόν ἐστιν ἕκαστον τῶν ὄντων, δηλούσῃ προσέοικεν,
Is this some rhetoric figure? For straightforwardly it would be: [οἴησις] προσέοικεν τῇ ψυχῇ δηλούσῃ οἶσιν ἐπὶ πᾶν πρᾶγμα, οἷόν ἐστιν ἕκαστον τῶν ὄντων. So, he substitutes here G for D.
Again, in 424a,
τοῦτο ἔμοιγε δοκεῖ, ὦ Σώκρατες, ὅπερ πάλαι ζητοῦμεν, οὗτος ἂν εἶναι ὁ ὀνομαστικός, ἂν εἶναι seems to depend on δοκεῖ, and the subjct neutral touto is changed to οὗτος …why all these gymnastics?