Number one is a known issue [edit: introduced with or around Awakening's release, IIRC] shared by the Sophon and Lumeris quest reward laws. The devs are aware, but we don't have an ETA on a fix (if I remember a comment from The-Cat-O-Nine-Tales sometime last week correctly). The second sounds familiar, but I don't remember the thread.

Second is a known issue too

https://www.games2gether.com/amplitude-studios/endless-space-2/forums/114-bug-reports/threads/34933-1-5-8-ritfborn-outpost-actions-unavailable

Might I add third? Stasis singularity doesn't stop invasions. At least it didn't last time I tried. Invasion proceeded normally and I was able to lose a system to it while in stasis.