On the first hand can you elaborate on us not needing to be good to often?

I meant purely from a pot odds pov. We're facing (aprox) 50c raise into what's now a $2.50 pot... we only need to win the pot 20% of the time to break even. He obviously has flushes in his range, but what else? QJ for sure, maybe AT KT K9, who knows? It's 2nl and people do crazy things, like shove 2pr at river when they should just call. And it's not a problem when he has QJ, we still make money from the call. Don't forget someone else put money into the pot, you're chopping that so there's direct profit. And by the river, there's a lot of dead money in the pot, We're putting 50c in to get $1.50 back, which is obviously better than folding. So chopping is fine, and it's also good because it shows that he doesn't have exclusively flushes.

His flop check could be 99 slow playing, and 55 might still call pre flop because people at these stakes don't like folding pairs pre flop. It does depend on the villain, but don't assume people are folding 22 to a 16c reraise, even when they haven't yet put any money in. So 55 could be in his range. Also, A5, A9, 9Ts, K9, KT, you can't discount these entirely. He won't have them too often, but he only needs them occasionally for us to be able to make this river call. And then there's also the non-zero chance he does this with absolute junk, because he saw a pro do it on tv. QJ is just too strong to fold in this spot, especially given the really good pot odds we have.