I just obtained and finished leveling up Hornet Man. This was my strategy for getting him. I used Roll and Snake Man for this, but the latter can be replaced with just about any bot with a resistance or affinity for Nature.

To start with, I used Defense and Attack swap with Snake Man. I then Buster Relayed the boosts to Roll, who I proceeded to switch in and knock down the wooden barrier with via Roll Swing. By this point Hornet Man was at low HP, so I Relayed the boosts Roll got back to Snake Man, switched him in and finished him off with Wily Buster.

While I didn't beat the event itself, my strat for getting Solar Man was as follows:

Turn 1: Speed Assault w/ Rhythm who had Energy Module to take one hit

Turn 2: Defense Assault, Rhythm gets KOed

Turn 3: Sent in Roll, KOed with max power Roll Swing

Again, I didn't beat the event fully, but I actually got quite close while unlocking Solar Man and his weapon.