"For these Group 3 hands, I look to raise pre-flop with the first three hands (ATs, KJs, AQ), from any position"

"I will play Group 4 hands from any position, but look to raise only with AJ or KQ"

Why not raise 99 and 88? With any pocket pair (other than the monsters) you're either flopping for unders or a set (and often get a great pot if you hit it since a set is hard to read) or raising for a 1 on 1 matchup. 99 and 88 is strong enough to do the later with a modest raise. Buying out the blinds + small bets is a pretty good take with 99 or 88. If you're re-raised consider how likely they have you dominated with a better pair and consider folding.

Against another hand with 2 overcards (say AKo, but any two cards greater than your pair will suffice), most likely it's a matter if they make their overcard and you don't get a set. 32.3% chance of them getting an overcard on the flop with 2 overs. 50% chance of them getting an overcard on any community card. Assuming they have 2 overs... However, if you have 2+ callers the number of overcards increases and hence you're more dependent on getting a set, full house, strait or a flop+ with only unders at slimer odds.