Chimmy stated, in her ask.fm, that the drive has become too far/stressful since her family moved from the ventura area. from the new city to ventura, it's about a 3 hour drive.
i'm not too sure about Angelina's reason for leaving, but i do know that she didn't try out this season and then came back around the end of summer. so shes been having feelings of leaving for a while. id guess that she is just maturing out of it and has most likely just had her fill cheer.
who knows though. people will say that theyll quit something and be back right at it. same thing happened with KK. she came back about a month ago and just competed with the team for the first time this season at nca yesterday.