I would use one home partition. Install PCLOS first and mint second as husse said.
since they both use different DM (KDE and Gnome) you wont have changing settings that occurs when using the same DM from 2 distros (ubuntu and mint).
since you are doing a fresh install of both distros you can test it for yourself.
the thing to remember and check is the user ID set by both OS's for the first user when using a common /home. the first user ID mint uses is 1000, i dont know what UID PCLOS uses but fedora uses a UID or 500. different UID's will cause you heaps of problems, fixable but also a pain.