Before you go doing the “toss new parts“ boogie, post over to the 100 platform guys - get more eyeballs there most likely, same motor in the platforms.
It’s what I’d do - and why sometimes I ‘stink up’ the 200 guys with my 5.7/3UR -talk.
I know the timing chain motors, not qualified to comment to your 2UZ issue - but here’s the ”low hanging fruit” though:
Since you swapped coils position, and from the way I read the post, the coils aren’t the issue but you toss code for 5&7 with swapped coils too - how are the knock sensors tied / dedicated cylinders in a 2UZ?
If you swapped a knock sensor (assuming 2/bank 4/total - yes?) - theoretic / full guess here - there’s a 6/8 knock sensor that is identical to swap with?
-So-
If you can, swap your 5/7 knock sensor for the 6/8 knock sensor, see if you constantly toss the 6/8 code???
As to the coolant - any chance it’s just condensate since you live where ice is a common thing right now?
I don’t want to be condescending but since you’re a new guy, IDK your level of mechanical experience.
If you know all about condensate in a crankcase, great - alot of people don’t.
