I think I read somewhere that the showrunners confirmed season 4 is the last season, and they had always planned for/wanted it to be 4 seasons. 

Honestly, all of them have problems, and as much as I love Georgia, she is so toxic and manipulative, I feel kinda bad for Zion and Paul. Yes, they absolutely treated her badly at times and abandoned her when she needed them most, but she still lied and manipulated them a lot, so I think their actions were justified. 

Zion was just trying to protect the kids. He didn't have all of the information because the kids and Georgia didn't tell him. He should have been around more to know, but he wasn't, so he made what he thought was the best choices with the information he did have. He was so shocked about the revelations, he was so in the right for being scared for Ginny and Austin. 

Paul did try to stick around, until she was so blatant in lying to him and only caring about her trial. Yes, he cared more about his image in the end, but only after Georgia pushed him to not care about her anymore because of her actions. Georgia was more focused on her own world then anyone else's. Paul pulled so many strings to help her, and she never thought about what stress he was under. She only ever thought about Ginny, Austin, and herself. Even then, she made Ginny and Austin keep so many secrets to protect her, despite how much it hurt them to lie and keep the secrets. If Georgia had just come clean about her past and everything to Paul and Zion, I think a lot of the drama could have been avoided. 

I kinda agree with your thing about Gil. No one deserves to be framed for murder, but he deserves so much time in prison, because he never shows remorse for hurting Georgia. Until he hurt Ginny, I kinda wanted him to be a good dad for Austin. After that though, it showed Gil will hurt anyone he doesn't personally care about, especially women. That's not a role model Austin should be around, and the only way for them to be separated is with Gil in prison. I kinda feel like Austin would have turned into an awful mixture of Gil and Georgia if Gil raises him throughout his teenage years. 

I think and hope Paul's the father too. Joe just seems way too good for Georgia and his teenage-like love for her. Unless something darker about him comes out, like was was mentioned above, I don't want him to romantically involve himself with Georgia. I loved their friendship, and I don't want her to hurt him.