The way vortex deploys mods is via hard links, or sym links.... If you move all the files and such around, those break. Need to uninstall/reinstall the game and your mods for that to work properly. And just as an aside, installing games OUTSIDE the program files folders is a GREAT idea.....
And yes, you can install any 2.5 inch SATA SSD in place of your mechanical drive. I recommend the Samsung guys. They cost a bit more, but, better warranty, and longevity that the cheap fellers. Going to an SSD from an HDD is the single best upgrade you can do for your laptop.