Honestly? Probably not. if she comes back the show would have no plot considering that Mr.Agreste might be hawkmoth and Mrs.Agreste may be his motive in some way or another. Plus it's been established as a theory that one of the reasons Adrien was chosen for the black cat miraculous and deemed worthy for the power of destruction is because he has had major loss and relationship issues and all together a pretty sad life. He basically has a better reason than anyone to go on a villainous rampage destroying everything or be a horrible person to everyone but he never lashes out at anyone and wouldn't hurt a butterfly (See what I did there). This attribute was shown in the Christmas special. Ms.Agreste is the core for all of that dramatic irony and sobbing fits from fans so at least until the very end it is very unlikely.
I don't think so, she might come at the very end but that's a slight chance. I believe she'd show up at Season 3. I mean in Season 2, Hawk Moth's gonna do a face reveal at the end, and I don't think Mrs. Agreste is going to be there. If the least they'd find her but, can't get to her because of some barrier, and you know the new Villian? He/she might've captured her, and kept her locked away somewhere very very far away.