Fair point there, Latinum is probably the least used unless your going for completion and want the ship trophes and holo-emitters. And fair point on the additional omega, etc... Just thought of them as another form of XP myself. So, how many currencies is too much?
Yeh, this is not too many currencies. Try back at launch where every rank of exploration nebula had its own currency for gear. 3+lobi (not really a currency, more a collectors trade thing) is just fine in my opinion.
The projects stay, they open up store unlocks and the like, you would probably be better waiting till a higher teir to do the ones for better gear than the first teir versions.
You cant mail Energy Credits, you would have to get someone to hold them for you till you make your new character. Your best bet is probably saving up some Dilithium, trading it for Zen on the exchange and then buying yourself some more character slots.