@Tony8 the only issue eith Hotspot ting it it can drain the battery of wife's phone, and since you phone is on wifi the os might want to do updates etc, as it does not realize you are Hotspoting.
Share plans are baked into the pricing of the big three mainline brands. They are generally only economical if you have more than two family members or have more than one device of your own where you pay a bare minimum for the second phone.
@katrina1, I have not encountered any family plans offering better deal than Public Mobile. If you know of any, please share.