Most do, but some don't. You can probably be safe without cash because most vendors overlap in product.
Yes
Bring some cash & it won't be an issue.
As above
I believe a good majority accept them.
This really depends vendor to vendor but the market does offer an "atm" that provides wooden chips that can be used at vendors that do not take debit cards. I believe they charge 2 dollars for that service kinda like using an ATM not associated with your bank.
Thanks! Your answer is awaiting moderation.