I like your reverse etas to give sate, meaning to please, but I can't find a Makarios reference to ETA (of course Basque separatists call themselves ETA). The only initials I found were EOKA which was in favour of ENOSIS, ie union with Greece!
Eluate - the only part of the wordplay that I understood was ate - took in.Eluate is the purified liquid, but where the "elu" comes from I couldn't find.
When he started to contribute I thought they were quite easy, but now as you say,they are often obscure. Also with Mephisto generally nowadays, there doesn't seem to be the wit that there was when I started doing them - oh, many years ago.