Some casinos will not accept a Cashier's check as it's considered a 3rd party check as strange as it sounds. Check with the "Cage" of the casino you're going to visit prior to your trip.
Nope...not at least the ones I have cashed them in. You just need proper ID and they turn them into cold, hard cash. Not that I ever had any difficulties with the American Express cheques, but the Visa ones probably work in more places (other than casinos). AAA uses Visa now for their cheques, so that's usually how I roll.