The typical distro's installer will just take care of setting up GRUB for you, don't worry about that. I'm doing something similar with my home partition, except I made a home partition with all the expected user folders ~/Videos ~/Documents ~/Music ~/Games etc and then used overlayFS which keeps ~/.config/ and the like separate for each OS partition while letting me share everything else.
The typical distro's installer will just take care of setting up GRUB for you, don't worry about that. I'm doing something similar with my home partition, except I made a home partition with all the expected user folders ~/Videos ~/Documents ~/Music ~/Games etc and then used overlayFS which keeps ~/.config/ and the like separate for each OS partition while letting me share everything else.