Sizing I think you could have gone a tad smaller to $2.20, not a big diff. I don't mind your 4bet but I would really think about calling if the opening raiser is kind of weak and you don't expect them to get too tricky.

I agree with Harvie about a smaller sizing achieving the same fold equity against this player type.

As for the idea, I like it and think the hand choice is a good one with the blockers. As played I doubt he's getting funky with you as cold 4 bets at 25NL are nearly always KK+.

I think this is fine and I actually think the sizing is ok with the other guy in the pot (I use it a lot), maybe I could tweak this myself then and maybe we go 2.30 as a middle ground but it shouldn't be much to worry about so w/e.

About this guys hand. To be perfectly honest I think you can pinpoint it to AA when these guys 5bet half a stack like this. I've had a few of these spots with KK which of course I won't be folding, but these 5bets to 5.50 type sizes almost always I see them turn over the rockets because I guess they do it so you might once in a while have room to 'bluff' over the top if it's not a cooler. Not sure how often that works out though lol.

+1 to smaller sizing.

I think this is a reasonable hand to cold 4bet bluff if you decide that you need a cold 4bet bluffing range. I'm not entirely sure you do at 10nl but if you're 4betting something like AA KK QQ AK (34 combos) KQs (4 combos) then there isn't much your opponent can do about it. For blockers, this hand works pretty well. If you see a flop this hand plays reasonably well also.