Also from a 5NL player lol ....

i think u should raise more pre with those hands, i always found 4x or 5x let in too many limpers at 2NL, and u don't wanna play with more than 2 others in the pot.
I agree u should have re raise much more on the flop, i usually go for pot size or more.

as played, I would have called the flop, then just call /check the rest. I think the range u gave him was a little tight.

basically you could reasonably put him on 77+, Qx, A3s. I think the majority of the time he's gonna show another pp or a 3. I find at 5NL as well, ppl defend their blinds with rediculous hands

I usually just try to keep the pot low in these situations.