Pre raise sucks imo. You've bet 2bb +1 per limper, it's just weak. My standard raise is 4xbb + 1 per limper, 12c in this spot, but I guess 10c is ok too. I only ever raise this weak with crappy pairs that are extremely likely to win a multi-way pot if it hits set.

I agree c/r is bad at flop, I much prefer to take a b/f line on this flop. Our kicker isn't great, there's a pair on the board, there's two others in the pot, it just sucks.

As played, this is a fold.

"My question now (although I'm severely off-topic) is can we make some general assumptions about the ranges of players at 2NL? "

As suggested, get PokerTracker or a similar tool. You can see at a glance who is playing a lot of hands and who is playing tight, you can see a player's tendancies to limp or raise, you can see how often they fold to a 3bet. It's an essential tool for me.