I recall there being something in Damascius' theory of time with a similar slant, namely that past, present, and future reflect the relations of causal or logical priority and posteriority between intelligibles.

It is a bit funny, though, to see the gods (metaphorically) resigned to the past.

Future me when the unwritten doctrines of dr. Greig are finally released:

Are they perfect insofar as no essential component is missing from them?

For Eternity, on the other hand, this question cannot be raised because it has no distinct parts in actuality. Because of this, Proclus argues that it transcends the distinction between perfect and imperfect (ὑπερτέλειος).

Additionally, in the Timaeus-commentary, Proclus argues that Eternity is the first Whole because its internal distinction between one and being (as in Plato's Parmenides) exists only in a concealed manner (κρυφίως). So, for other, lesser wholes we can raise the question: ...

The eternal being is thus whole in an axiological sense because all of itself is present to it at once, and so cannot deviate from its natural state. In this respect, the whole for Proclus is not just a logical concept (as in, a given set of elements), but also always an axiological one.

These two kinds of beings are in turn linked to two instances of participated goodness: a) goodness which is stably possessed by its participant (= an eternal or perpetual being), and goodness which is inherent in a weaker, changeable participant (= a sensible particular).

There, he argues that the whole is something which never gives up ‘either its essence or its proper completeness’ (οὐδὲν γὰρ τῶν ὅλων ἢ τὴν οὐσίαν ἢ τὴν τελειότητα τὴν οἰκείαν ἀφίησιν). He then contrasts the true, eternal whole to the 'partial being' (μερικόν).

In the Platonic Theology (book, ch. 27), Proclus gives a similar explanation to your analysis of the Elements of Theology, but he also adds an axiological argument for why Eternity must the primal Whole. 1/?