@Sandra
I prefer the Mint Cinnamon. I would say because that is the version that comes from Mint developers and has most development. But all three are perfectly fine.
Note there is a forth, LMDE. It only comes out of the box with Cinnamon. But based on Debian instead of Ubuntu. It is more to develop the concept to use Debian, but really interesting and possible to use, but I recommend standard Mint firstly as starting point.
@Sandra
All above photohraphy suggestions are free and open source, so you can easily try them. Note that metadata, store in file vs sidecar and how each manage differs and needs understanding and consideration.
@Sandra
Photo as other suggested. But for me is digiKam starting point for catalog and editing, but also RawTherapee for editing (Darktable potential alternative). More incl less complex alt exist. I would also add Gimp for more Photoshop-like editing.