Your flop play was pretty bad, you hit top set on a pretty scary board. At this stage I would not give anybody credit for 67 (while call a PRF with it?) but pocket 6 or 7 is a possibility.
Villian's 2 behaviour on the flop is wierd, he called your initial bet and then reraised villian1, this screams a made hand - I would put him on a set here and pushed.

On another note, your assessment on the river mistake is correct , however your conculsion is wrong - you should have raised him by the max amount you believe he will call