Where's all these claims of male fights coming from? I kept three males and one female together with absolutely no problems. Emps are a fairly communal species and fights in general are rare (after initial territorial displays). I've seen more aggression from gravid females than anything else.
OP, if you really want to open your options, wait for your male AND get another male (or the potentially gravid female from the store). Sure, you may not know how long your male has to molt, but you also don't know how long your adult female has left, either -- or how long an adult male from a store will last.
More options = better.
