A good way to show the reader more of Arilou culture would be to let the Vindicator crew get some shore leave on Falayaralfali.
Something tells me that that would be a bad idea.
Welcome back to Falayalaralfali, Captain.
Perhaps, in the fullness of time we will let you visit the surface of our world.
There are many beauties here unmatched anywhere... the Mountain Clouds of Thought
the Tangible Wish... the Dark. Unfortunately, you are not yet... acclimated.
Premature exposure to these would render you...numb.
Hello. We are pleased to see you again. Have you any numbness yet?
Good. It should be too soon for that. Too soon by far.
I don't know about you, but that doesn't sound pleasant. I don't think human beings have quite what it takes to endure Falayalaralfali at this stage in our evolution.
As far as the Star Control fanfic/novelization goes, Grakelin, I heartily endorse it! It sounds like you already have some very good ideas, and going to this group of SC2 fans to ask questions is a smart thing as well. I'm sure they'll tell you if something isn't adding up.

Just a few pieces of advice from little ol' me:
I've found that by reading through the SC2 manual, role-playing resource guide, and actual quotes from the game, you can come up with a vast wealth of information on the aliens that you might not have noticed or even thought of before. I mean, before reading the manual thoroughly, I would've never pictured the average height of a Yehat as being just shy of ten feet!
The pages that contain the game dialogue are
here if you need them, by the way. Just remember to take "starcontrol" out of the URLs for the separate pages, otherwise they won't work.("
http://starcontrol.classicgaming.gamespy.com/starcontrol/sc2/quotes/chmmr.txt" becomes "
http://starcontrol.classicgaming.gamespy.com/sc2/quotes/chmmr.txt", for example)
Sometimes it's just the little things that can make dialogue seem odd or unbelievable. Going through the quotes is a good way to get a feel of the attitude and "voice" of the different races.
For example, the Utwig tend to name and describe things in very grandiose ways. The Spathi High Council speak much more boldly and can be more sarcastic than regular Spathi. The Umgah have quite a large vocabulary despite some lingual quirks like leaving the words "is" or "are" out of their sentences (ie. They can use such words/terms as "gratitude", "compulsion", "vigorous", "sufficient", "juveniles", and "legitimate" correctly and effortlessly). The VUX seem to be very quick, creative thinkers, and are eloquent as well. This can be seen in the way that they can rattle off a variety of long and descriptive insults and exclamations without pause or difficulty.
And so on and so forth...
I hope that's of some help.