wow, where did you find such a table? Its almost not worth even wondering about because the odds of finding a table with 5 fish and full stacks is like winning the lottery :)

Id raise all the hands that played well multiway in big pots, and limp anything that could make a nut hand but isnt worth raising pre. Altho I like the idea of juicing the pot with a minraise with hands like 55 and stuff so that when you flop yahtzee you can get stacks in much easier

I guess minraising your whole opening range is fine for the reasons you mentioned....If those guyse are braindead beside theire passiveness you can simply limp or minraise a lot of speculative hands(would def widen your openingrange if nobody is going to 3bet) and just 4x(maybe even more?) your strong hands AQ+/TT+

But its important that you have more reverse implied odds with some of your speculative hands...esp small/mediocre SC´s due to the fact that they cant resist calling K4s in MP vs your UTG open :)

But thats also the reason you should open your AK bigger if they dont recognize, cause they also cant resist to call you down once they hit TP with K4s

Yeah, I think you shouldnt make plays post that require FE, most of them wont fold Ax,and low pairs with any kickers, thats why I learned today when a player like that called me river with T4o with pair of tens , T came up in the river, with 98Q2T board, I tried to represent flush and cbetted flop, so when you have it, get stacks in.

That doesn't seem loose-passive to me. 30/10 might be, but the players you described just sound like passive-regfish.

With that said, because they're passive it means you can probably get away with opening hands that you might have issue with against players that 3bet, or play back aggressively postflop. I play 10nl at the moment, so put up with players that are much more loose-passive than this.

UTG range I'd remain the same. I'd probably remove lower PP's (22 - 55), and the worse of the suited connectors (98s, if you include it). If you open a lot of suited Ax hands UTG, I'd remove the worst of them too. What you could start doing is opening more KTs UTG, QTs as well. Hands that have a lot more top pair value.

Opening sizes I've been experimenting with lately. For me lately I've been doing 2.5x as a standard. Means that I lose .5bb less every time I X/F, and to make up for the .5bb I only need to bet slightly larger postflop.