It's a complicated issue for them, so of course it's going to 'drag' as you put it. It's not as simple as resolving it in only a few chapters and it's going to continue being an issue until they resolve it or decide to truly cut ties and move on from each other. And just like in real life, it sometimes takes a lot of time to figure these things out.
I think she should be honest with her mate about what his father is up to. Her mate is the Alpha too. Surely he could counter his father's orders if he were to try and go through with kicking Cassie and her family out. By doing the father's bidding, I feel like she's really just using it as an excuse to once again not truly see where things can go with Alarik. She didn't even try to find a way out of this at all. I hope Alarik realizes something must have happened and doesn't give up, and doesn't do something stupid (like screw some chick again) before he does realize.
Team Lucas of course.
Honestly, I'd still be upset at his ignoring her, especially after such a huge revelation on her part. He saw how terrified she was about him not wanting her anymore, how could he not realize how that would feel for her, waking up alone the next day, being ignored all day? So as much as I sort of get his reasons, I'm still not ok with what he did. Also, if I were her I'd be kind of upset that he didn't invite me to such an important charity event. He's invited her to so many other events, but when it is something truly important to him on a personal level, he doesn't. I can't help but feel like he should have wanted her there even more because you should want the people most important to you to be a part of the things most important to you. I think she has legit reason to be upset even if the cheating accusations issues hadn't come up. I think part of the reason she was so willing to think the worst was that she was already hurting from his ignoring her. As understandable as his reasons were, it doesn't mean it was the right way to do things. In any case, I really hope she doesn't listen to him and goes to him and demands they talk things out. Time apart is stupid. Fight for your relationship!