1- yes, technically all species are, but I do not ensure you would want to
2- good luck with that, each planet has its own imperial/metric debate going on, but we have sort of put down a Rosetta stone for these different cultures meetings
3- depends on the species, each one has a historic event that they mark as the beginning of time, Bipels have a written history to the point where they conquered the final species before them, sort of like if we counted the year the last neanderthals died as 0.
4- suprisingly enough, the gasfolk are phosphate based
5- jungian conciousness is interplanetary, they have many of the same theories, but with different names and styles
6- alien music is fucking everywhere, we have the RY24 folk working on analysis and import, one of the perks of the job is downloading any music from any planet, and claiming to be doing work analysis. I personally like the sort of theremin bath electro jazz weirdness that is the grays music, but other people are good too.
7- got to say amber.
8- 11 of 13 do, the other 2 are just gaseous entities, and a psychic form of photons projecting themselves infinitely, never seen them, since no photos exist showing them, but goddamn do they sound cool.
9- Xeno containment isn't possible alone, we have to do semiannual meetings with each species to discuss containment issues, and sign charters with each other to help with key issues, like not having people eaten by alien beasts brought by idiot hybridders
10- actually the lionfish folk since they had their home world destroyed, although technically no longer alien, were still a species that was not known of by any others.
11- Engullas, tall, semi humanoid, large eyes, wide smile, pale white skin that has chromatoids for invisibility. fantastic guys, haven't seen one with ill-will yet. even when they are in trouble, its only because of practical jokes.