Well common cories like (paleatus,aeneus,trilineatus,sterbai,panda) can stay in high ph water...i know that because i did have them staying with my mpimbwes before... but theres a side effect though. They can't get big. My 2 year old cory at that time stayed at 3cm for all its time there. My newer cory fewer purchase of arcuatus however is blowing up to 3.5cm from a mere 2cm individual in a period of 5 months...

FYI...ur cichlids will not try to swallow them unless they are so much bigger and if they do attempt to, they will have a terribly painfull lesson as corries have spikes (sterbai's have mild poison in their spikes). However if the cichlid is too persistent in trying to gobble down the cute cory, u may end up with 2 dead fishes instead. Cory don't go in easily so the cichlid will suffocate and also die with his cory meal...