That's a good question! The text in the T&Cs hasn't been updated! Neither has it been updated in the section that describes the use of tier-related upgrade vouchers (though it can be assumed, that there was no need for the latter to be upgraded, since the way it was written theoretically still covers everything).
I have successfully upgraded Family fare tickets with vouchers, so I would assume the same would be possible with miles as well, however, since the only way to upgrade with miles is via customer service anyway, I guess you'd have to ask them for a definitive answer to that (since the two upgrade methods already differ, in fact favouring the use of vouchers, in that with miles all PUT fares are excluded, whereas with vouchers just light PUT are, so even though very unlikely, there could be a different treatment regarding family vs flex too).Yes. Start with 1 passenger and keep adding until availability disappears. It isn't common though for Aegean flights to offer 4xI.Yes, but they'd have to split the booking for that, so perhaps a thing to consider .Yes (however regarding "days", not "hours") and no. It depends on several factors (most of which are quite easy to guess) .