In your original post, you wrote:
it's getting out of hand here, where EVERY non-human's name is entirely invented.
Does anyone have any advice on keeping alien names reasonable (i.e. making them seem authentic, reasonable, or fitting the characters)?
Perhaps you need to step back and reflect on what you want as help from us.
You seemed upset that all of your non-human names were invented. Non-human names have to be invented. You want 'authentic' names and human names are not authentic for an alien. Any combination of our alphabetic characters that would seem 'alien' would probably be impossible to pronounce.
You shot down Red61544's idea of something like - "My name is unpronounceable in your language. You may call me 'Joe'." So substitutes for weird spellings are out.
In the first paragraph of your reply to my post you said:
Again, using 'trends' falls apart in a multi-species society,
I provided you with several conventions that could be applied to create names for different alien races. You can come up with others. You use one naming convention for one race, a second for the next, etc. It doesn't matter if you generate one name or a hundred, just stay with the specific race's convention. But then you went on to say:
as few of the aliens the protagonists meet belong to the same species (other than spouses), so there really IS NO consistent naming or word-use trends between any two characters.
That puts you back to where you were at the start of the thread, CW. You want multiple names that don't follow a single convention. That means you will have to create them yourself.
Your second and third paragraphs were you pontificating on the cultural aspects of the societies you are creating. I notice you do that a lot. Your pontification added zero to how we could help you. I don't know about the others in this thread, but I get the feeling you are going to shoot down every idea anyone comes up with to help you. So other than us presenting ideas that you can shoot down, what are you looking for.