You cannot use the bank account if the account number and sort code remain the same. It is possible to have the bank change them, and then you can use the account again.
Yea, if the PayPal is limited that bank account is done. It is a controversial subject but some people have had eBay taken down then able to close out the PayPal and reuse that bank account a few months later.
I think everyone one here will say you are safer getting a new bank account. But if it is one of several stealth's I understand the hassle of getting new Bank Accounts. I actually find it to be the most difficult part. Then you may have success if it is the situation I described above. No doubt there is risk for possible link.
Depends, after a year or so yes. Oddly I've keep the same paypal and attached 8 diff ebay accounts after ebay suspensions without linking, though like I said I waited quite awhile before doing it and it's also a merchant paypal account.