hi, there seems to be lots of separate points being discussed in this interesting thread, and so I have tried to separate out the different questions and then have given my own suggested answers to each below:
1. Does putting a ppl in the aorist indicate that its action occurs earlier in time than the main verb?My answer: No. Only future and future perfect ppls indicate temporality. Present, aorist and perfect ppls don’t. The key authority for this is Chapter 2 Part 2 of Duhoux 2000. I have scanned it for you (link 1 below). To summarise it, Duhoux shows, going through one-by-one, that present, aorist and perfect ppls can each be used for actions occurring:
- before the moment of speaking (s40) or before the action of the main verb (s43),
- at the same time as the moment of speaking (s41) or at the same time as the action of the main verb (s44),
- after the moment of speaking (s42) or after the action of the main verb (s45).
Duhoux’s analysis shows that present, aorist and perfect ppls can each be used for any timezone. Therefore, they don’t indicate temporality. See also the bottom of pg 310 (link 2 below) where Duhoux states this explicitly.
2. Can the fact that the action of the ppl occurs earlier in time than that of the main verb be a factor (among others) influencing a classical author to put the ppl in the aorist?My answer: Yes. Sometimes it plays a role, sometimes it doesn’t. There are at least 9 concrete factors (and other less concrete factors) which may play a role in a classical author’s choice of the aorist. There is a list of these factors in Chapter 4 of Duhoux 2000. I have scanned it for you (link 3 below). To summarise it, the following are some of the concrete factors which may influence a classical author to use the aorist:
- Factor (A): where the action of the verb involves a change/modification to something, e.g. δίδωμι (see bottom of pg165 to top of pg166).
- Factor (B): where the verb has the preverb ἀνα-, ἀπο-, κατα- or εἰσ- (see para (d) on pg167 to middle of pg168).
- Factor (C): where the verb is negatived (see para (d) on pg169 to middle of page 170).
- Factor (D): where the action of the verb occurs before the moment of speaking or before the action of the main verb (see para (f) on pg170 to middle of page 171).
- Factor (E): where the verb is qualified by an adjective of suddenness (see para (j) on pg172).
- Factor (F): (for specific verbs) e.g. Lysias prefers to use the aorist for verbs in the list beginning with ἀγγέλλω on pg166; Isocrates prefers to use the aorist for αἱρέω and τελευτάω (see bottom of pg166).
- Factor (G): (specifically where the verb is finite) if it is in the subjunctive, and also (for Lysias specifically) where it is in the optative or imperative (see para (g) pg168 to top of pg169).
- Factor (H): (specifically where the verb is a ppl) if it completes the sense of a main verb in the aorist other than (for Lysias specifically) where the main verb is ὁράω or φαίνω (see para (b) on pg169 and bottom of pg 171) (NB: for background reading on this type of ppl completing the sense of a main verb, see link 4 below (Smyth calles it a “supplementary” ppl) and link 5 below (Goodwin calls it a “predicative” ppl)).
- Factor (I): (specifically where the verb is an infinitive) if it (1) depends on a main verb in the present (see para (c) on pg169) or (2) is introduced by πρίν (see para (g) on page 171).
- Factor (J): (specifically where the verb is imperative) if it (1) is a specific command to someone other than when calling witnesses in a trial (see para (i) on pg172 and para (γ) on pg249, not included in my scan sorry) or (2) is a command from a human to a god (see pgs245-246, not included in my scan sorry).
There are other factors as well, as listed in prose comp books. But this list above alone shows that there are many factors which may play a role in a classical author’s choice of aorist. Temporal sequence is just one of the factors, and no factor is determinative on its own every time (see bottom of pg 311 in link 2 below, and s142 on pg175 in link 3 below).
To take some concrete e.g.s: I flicked through my Lysias OCT to the last paragraph of each speech, which are often full of commands (i.e. please let me off/please punish him), and looked for imperatives with associated participles. I found the following e.g.s, where the ppls differ in tense – some are aorist (ἀναμνησθέντες), some are perfect (μεμνημένοι): but I don’t think we can assume that the aorist ppls are, by virtue of their aorist tense, indicating different timezones to the perfect ppls. As shown above, the temporal sequence is just one of many possible factors (i.e. Factor (D) above) which could influence the choice of aorist for the ppls in the third and fourth e.g.s below. Another factor which could equally well explain it – without reference to temporality at all – would be Factor (B) (given that the aorist ppls begin with ἀνα- whereas the perfect ones don’t). Other factors could also be relevant: my point is that there’s no reason to assume that the aorist is indicating temporality in the ppls below, i.e. that Factor (D) is the determinative factor in these cases.
- e.g. 1: Lysias 3, 47: ὧν ὑμεῖς
μεμνημένοι τὰ δίκαια ψηφίζεσθε,
- e.g. 2: Lysias 10, 32: ὧν
μεμνημένοι καὶ ἐμοὶ καὶ τῷ πατρὶ βοηθήσατε καὶ τοῖς νόμοις τοῖς κειμένοις καὶ τοῖς ὅρκοις οἷς ὀμωμόκατε.
- e.g. 3: Lysias 13, 95:
ἀναμνησθέντες οὖν ἁπάντων τῶν δεινῶν, καὶ τῶν κοινῶν τῇ πόλει καὶ τῶν ἰδίων, ὅσα ἑκάστῳ ἐγένετο ἐπειδὴ ἐκεῖνοι οἱ ἄνδρες ἐτελεύτησαν, τιμωρήσατε τὸν αἴτιον τούτων
- e.g. 4: Lysias 24, 26: ἀλλὰ τὴν αὐτὴν ψῆφον θέσθε περὶ ἐμοῦ ταῖς ἄλλαις βουλαῖς,
ἀναμνησθέντες ὅτι οὔτε χρήματα διαχειρίσας τῆς πόλεως δίδωμι λόγον αὐτῶν,
3. Given that anteriority in time is a factor influencing the choice of the aorist (see Factor (D) above), does this mean that the aorist ppl does, in fact, indicate temporality in a downplayed way?My answer: No. See the answer to question 1 above: aorist ppls do not indicate temporality. It is tempting to think that, given that anteriority in time is a factor influencing the choice of the aorist (Factor (D)), all aorist ppls indicate temporality in a downplayed way. But this would be like arguing that, given that having ἀνα- as preverb is a factor influencing the choice of the aorist (Factor (B)), all aorist ppls indicate the sense of ἀνα- in a downplayed way.
4. Is it justifiable to put the circumstancial ppls (φαγών and πιών) in the aorist solely on the basis that the imperative that they go with is in the aorist?My answer: Not as far as I know. I have seen authority for this in relation to ppls which complete the sense of the main verb, i.e.
supplementary/predicative ppls (see further Factor (H) in my answer to question 2 above), but not in relation to
circumstantial ppls. Not to say that it isn’t correct, just that I haven’t personally seen any evidence/analysis on this point (and if anyone has any studies on this, I would be grateful to see them).
5. Was modus wrong to propose that eating and drinking could be written as circumstantial ppls with imperative εὐφραίνου (rather than writing them as imperatives)?My answer: No. Circumstantial ppls can go with imperatives: see the Lysias e.g.s above in my answer to question 2 above.
6. Which is more classical in the end: puting eating and drinking as circumstantial ppls, or as imperatives?My answer: I’m not sure as I’ve seen both types in classical literature: personally, I would follow the Louvre cup which I linked to earlier in this thread or something else having classical authority.
cheers, chad

Link 1 (Chapter 2 Part 2 of Duhoux 2000):
http://mhninaeide2.webs.com/Duhouxextract1.pdfLink 2 (Chapter 9 Part 2.4 of Duhoux 2000):
http://mhninaeide2.webs.com/Duhouxextract2.pdfLink 3 (Chapter 4 of Duhoux 2000):
http://mhninaeide2.webs.com/Duhouxextract3.pdfLink 4 (Smyth s2088 and ff):
http://www.perseus.tufts.edu/hopper/tex ... thp%3D2088Link 5 (Goodwin s112-113):
http://books.google.fr/books?id=BvAQAAAAYAAJ&pg=226