Some balls just can be really picky and only like f/t for a certain period of time and then only like live all of a sudden. Some people would say let her go hungry until she will eat f/t again, but live for a snake really isn't that big of a deal.

It depends on what your snake likes when feeding multiple prey. One of our balls has been raised on live, so it's just what he gets since we adopted him. He was also raised to eat in a feeding container so he gets fed in a tote haha. I give him one live mouse, then when he's done and moving around, he gets another.

For frozen, some snakes will still be eating one mouse and be a voracious enough feeder to grab another one while they are still swallowing the first.

It's good to feed one prey at a time, so I would wait until they are done swallowing the first to offer a second, f/t or live.