I see that he hasn't snooped into Chrome at least
It would be trivial to mount a drive without touching the files on it (such as Chrome history). Any Linux live USB offers read-only mount support.
Yeah, I'll move everything to new wallets just in case, you can never be safe enough. On top of that, if we suppose that he has snooped through my files, he could potentially try to compromise the wallets at a much later date. That way, no accusation can actually be directed to him.
Absolutely. If I were you, I would definitely pay the transaction fee to move the coins to a new wallet.