AQ is definitely strong enough to open the pot. At these stakes you're going to get lots of weak aces coming in against you regardless of your raise, so you're fine there.
As far as cbetting and all that, it's really opponent specific. If the guy never folds to cbets, then I'm not pushing it. You make money at these micro games from players going to far with junk. There's no real need to force situations, trying to take down every pot. You'll do much better betting solid values.
The 3bet question is tough and again entirely depends on the opponent. I steal quite liberally, so if the player has made an adjustment and is now 3betting me wide, then I'm going to try and get tangled up in a big pot, because I'm likely getting the best of it. However, if the blind is letting you steal at will, and is now taking a stand, it's likely because he has a real hand. AQ probably doesn't fair well against his range...lots of micro players reserve 3bets for KK+ and maybe AK.
I didn't notice the short/middle stack part either. With a short stack AQ is phenomenal. I'm looking to get a good part of the effective stacks in preflop, to create a favorable situation where I can get my entire stack in ahead of my opponent's viable calling range. Short stacks want hands that are able to make top pair and then commit with them, so AQ is great. Hands like KJ and KQ also go up in value, and stuff like SC's or small PP's are pretty worthless since their value comes from implied odds
, which you don't have short.