Well, I think it was the fact that they were souled vampires was what made them targets.
I think I pretty much agree with everything you wrote. And The First only apparently started to move after Spike got his soul...

About Angelus then copykween had the brilliant thought, that maybe Jasmine wanted Angelus to kill Connor (since killing his family was pretty much Angelus's MO) and thus get rid of the only person who could kill her... I really like that. I think - it been too long since I watched S4, so I can't remember all the twists.