Can Non-Robot Minions be Reclaimed via Microbot Reclaimer?
As included in the Pretty Pretty Smash Up rules, page 10:


  "A minion" or "minions" means any minions in play unless stated otherwise.


This means that minions in your discard pile are not affected by an action that states "minions".

So no, minions in your discard pile are not classed as Microbots due to the Alpha as they are not in play.