You definitely do not want your BP to imprint on a prey item that is not readily available or that is expensive, this could be an issue even more so if you had to re-home your animal.
Hatchling are generally started on hopper mice moving to small adult and adult rather quickly, at this size a small mouse (between hopper and adult will do)
If you BP has never took a meal with you, feed live for at least 3 to 4 feeding (remember your priority is for your BP to eat for you). Once established you an attempt to switch to F/T.