chewbacca attacks your opponent's crossroads (but it makes their fools gold a lot better)
I don't follow.
Fool's Gold looks for 'Fool's Gold', 'Provinces', and 'Gold', depending on the time. If all cards in the supply are named 'Chewbacca', none of those checks would ever occur, so Fool's Gold is completely neutered.
Crossroads always checks to see if this is the first time you played a 'Crossroads'. However, with this, you played 'Chewbacca', not 'Crossroads', and thus the check fails even the first time you play it, so you're right that it attacks Crossroads.
So, any card that says 'Gain an 'X'' wouldn't fire, whether that's Silver, Gold, Copper, Duchy, Estate, etc. But since card types are not affected.
Tournament can still win you a Prize (JUST KIDDING, your Province is now named 'Chewbacca', but at least the Peddler effect can't be stopped).
Dark Ages and Plunder cards can still gain Ruins and Loot, as those are card types.
Curses also are unaffected, as Curse is both the card name AND the card type.
You could still gain any Spirit from exorcist, but all other named spirit gainers fail. Leprechaun won't actually get you a wish if you play him just right either. Basically every card from Cornucopia is thus rendered worthless. You'll always guess right for Sorceress, but
Cards that benefit(?):
Farmland can now pick up itself when you buy it and use its insta-remodel effect, allowing you to keep chaining it.
Wishing Well becomes a full Laboratory
Mystic and Sorceress also work every time.
Rats can't pick up another Rats, so is just a nice cantrip trasher
Doctor just trashes the top three cards or rearranges them
I need a rules clarification on the meaning of 'Copy'
Can I choose to discard every single card I have in Exile when I gain any other card?
Can I buy a cheap card then Duplicate it to grab a Province?
Does Warlord make it so your opponent can only play two cards total?
Or does 'Copy' check on everything, name, types, card text, etc...?