So i legit did some digging and I think I have found out at least who did the voiceover for Mama Earp and is most likely going to be well could be Mama Earp. She is Canadian and an actress which is useful as this is where the show is made and produced by a Canadian team and main cast, and has worked on some big shows but for some reason hasn’t really been credited on IMDB for it. Here we go - this is her IMDB page:
This is the IMDB page for the credit for Wynonna Earp. Actress Paula Kaye. So I did some googling and legit ended up conveniently on her twitter page, where she clearly puts on her description #WynonnaEarp and well if this could not be actress to play her mum after you see her picture alone, I am not sure who else couldn’t be.
This is certainly the woman who voiced her, conveniently has dark hair, blue eyes like Wynonna and could pass as her mama.
If you look at who she follows, it is most of the cast. So I think its clear that she will be Mama Earp next season.
So I think ladies and Gentleman, this is Mama Earp.