NH. I play it the same, although at game speed I might reflexively bet the river for value when checked to but this is pretty low in my range after b/c pat/pat action so checking behind seems fine. I think raising the turn donk bet would be FPS.

I would pat. And I agree that checking river is best here, if we both pat.

So last night I played another hand where the action was the same. This time I had 86532 so I bet. The guy goes, "What that's it?" and rolls over 24567 lol

In general i thought this hand may have been too strong to freeze?

It was one bet in on the turn, pat-pat, and then he just check calls river with #4?
Nice game.

Yes

In another hand with another guy we were playing badugi on the last draw where we were both drawing one. He bets out, I raise with a seven badugi, he calls with an A346, and looked at me like I was a maniac

Confirmed maniac.

I crunched the exact numbers on this one, incorporating everything including card removal and his BB calling range which essentially makes all hands (including 98764) possible in range. Numbers assume he is betting any 98 or better.

% win pat vs that range - 50%
% win break vs that range - 25%

Given the pot size that is a 1.31 big bet difference, which is too much to make up in the river betting.

Note that range of possible hands does matter. Say villain raised from UTG and drew two. Mostly safe to consider his hand contains a deuce which eliminates many hands

% win pat vs UTG range - 38%
% win break vs UTG range - 23%

.81 big bet difference, so we are getting to the point where breaking is a consideration with premium draw.

But against UTG range, 97652

% win pat - 26%
% win break - 20%

.31 big bet difference, I'd call/break that and raise some % of a time as part of a mixed strategy