As for loading older versions, sure you can. I have PSP8 installed on my computer (the old JASC version!). But the best way would be to install that old program and then copy the supplies that come with it, and paste them into a “master” folder. That way, over time, you might only need to point PSP to ONE location instead of multiple, AND it will allow you to uninstall those older versions if you don’t use them otherwise.
I’ve got a PSP 9 CD still! Haven’t had it on a computer for a lot of years, but I just can’t seem to get rid of it. Nostalgia reasons.
So do you put things into the various folders in the master folder. This would have been so easy with the old folder naming conventions but confusing with the folder names with numbers. I am down to 2 locations in my file locations. I basically use the Corel# folders but if I download something and put it in the Documents folder, it is available since I also point to it.