I'm playing on EoS, using a Lv.100 Chimecho in Waterfall Cave with Maxed IQ (and Fast Friend). I usually hide in the wall, max my attack stats out and hold a Golden Mask, then hammer away at the Kecleon till I'm forced to move to the next floor by those gusts of wind. I also use the exclusive item Ching-Torc (for Chingling/Chimecho) to increase the chance of there being a Kecleon Shop on the floor. There usually is.
Kecleon recruit rate is -49.5%. So Lv. 100 (+25%)+ Golden Mask (+24%) + Fast Friend (+1%) brings this up to +0.5% - so 1 in 200 Kecleon should ask to join you.
I've done this manuveur about 5 times and probably defeated about 200 Kecleons, but not one has asked to join me.
Wanted to ask - Can I recruit Pokemon if I'm hiding in a wall?