For the texture smoothing, I think it might be having issues because it's expecting backslashes ( \ ) in the filepath instead of forwardslashes ( / ) because it was just made for windows before Reborn even worked on other platforms. Not sure if knowing that will actually help you with working around it though.
TBH that just sounds like a PBS formatting error to me (i.e a bug). False was probably supposed to be for one of the other fields like shininess with nickname left blank, but some of the values probably got shifted from a missing/extra comma or something.
I'm guessing it's because 'left' and 'right' have functionality on the nickname screen (to move the cursor) so those sort of override the typing for A and D when those are rebound to those directions. Since 'up' and 'down' don't do anything, the rebinding of those doesn't interfere with the normal typing for W and S
It's been a while, but yeah I'm pretty sure that was the reasoning. didn't want the existing theme to go unused, so it became "his" theme since he should now be the only one using it? don't remember exactly though.
I'm pretty sure there's a certain timeframe requirement too. don't remember exactly but try between like, midnight and 4am (you can set your computer clock)
If you mean the passwords mentioned in a past dev blog post for enabling certain game rules or features, That's a feature in development for Episode 19 - It's not in the current version