Problem is Reaper requires farming shoretrooper and deathtrooper - which don't unlock until 82/83. And I've NEVER seen Reaper shards anywhere outside of that single hard node.
5 rebel ships will technically get you into the Home One challenge, but it's unlikely to win it for you (if they're all just 5*).
Technically you can get into the Chimera event with Ghost, Phantom, Home One and one to four rebel ships, but again it's not going to win the fight.
So don't rush to enter those events as soon as you hit the minimums, or you're going to be very disappointed.
And @Kai_Mulai nailed Scimitar - that reinforcement/steath/retribution tactics is super annoying and highly effective.
