City councils would have to want and approve the moved convention. So you can cross out many cities in Florida, Georgia and Texas just based on that.
Nah. There're these things called State Troopers that Kemp and DeSantis can easily dispatch to overrun APD or whatever. Security for national conventions is never a strictly local undertaking, anyway. State governments are unitary, governors can overrule mayors or city councils by simple order and they hold all the keys to enforcement (which should be entirely evident, given that it's Governor Cooper who's threatening to cancel the RNC and not the mayor of Charlotte).