We got pet names the ROs would use for others, but what sort of pet names do they like to called?
Mori is the consummate attention whore and as long as there a single note of affection in it, you can call him almost anything and he'll be very >:3c about it. Gets extra smug if you call him baby.
Amir is partial to anything that feels comfortably close. A lot of his work involves theatric romance so when it comes to his close relations he prefers something earnest and simple to something grandiose. Amir is an accomplished polyglot and would find it particularly cute/endearing if you called him something from your cultural background/language etc etc.
Akello has a grotesquely sweet side so he's smugger than he should be to be called baby, sweetheart, honey, or whatever sacchariney thing you can come up with. Like Mori, he has no shame when it comes to terms of endearment.