I'll merge my mod into this and give it a whirl. It looks like you've put a lot of work into this.
I am curious on your thoughts about the changes to the minor races. With the Algorians, the friendly + capricious mix makes them like a bipolar friend. They are nice, but react to stressors "poorly". The Scavengers are even more unruly, as their problem solving techniques seem to start with "Take a deep breath... burn it all down... loot the ashes... assess your feelings...".
The Lummox are a bit bland, but I rather like the character of the other two.
My personal opinion, and I know everyone can do as they like, would be to keep the Algorians and Scavengers with their current stats. If you want to make the Scavengers mobile, tweak migration rules so that "unruly" no longer disqualifies a race for transport. If you want to keep the Gaiad on Gaia, make them sessile. It would not be difficult to imagine an uplifted race on a highly terraformed world being bound to that ecosystem. Or, let the Gaiad wander and make their environment compatibility for non-lush environments rather low. (Make them unhappy in Hive worlds.)
I think the idea of mobile scavengers, who are hard workers but a powder keg, could be an interesting challenge.
Kudos on all the tweaking you've done.