IWM licenses BT minis rights from TOPPS; I assume RPE does the same.
IWM produces their own molds, as part of their costs. It's my understanding that, once upon a time, IWM and RPE had an arrangement where each would share master molds (or just master minis?) for minis they produced that the other did not. RPE stopped doing that, so that arrangement stopped, so RPE didn't have anything new after that point unless they molded it themselves.