Best you can invest in is a 3M spray paint face mask filter, ill be around 40 monies but its worth it.
That will save your lungs.
If you are worried about touching the models then wear gloves when painting.
That will save your skins.
The most dangerous element in paint are the (heavy metals) that must not be breathed in or absorbed through the skin. Most at risk are ceramists and sculptors who deal with vapors!
For us painters (cadmium) paints are most toxic, so if you can avoid those you should be safer.
Oil-based paint is safer as it does not absorb into the skin as quickly as the water-based paint does, however the oil paint needs solvents that fume (odorless terpenoid) helps a lot with the fumes.
Quick browser search revealed some info like:
https://coloringfolder.com/which-paint-colors-are-toxic/
Color----------------Toxic Component----------------Harmful Effects
Yellow----------------Lead Chromate----------------Lung Cancer, Respiratory Problems
Green----------------Copper Arsenite----------------Skin Irritation, Eye and Skin Problems, and Cancer
Red----------------Cadmium----------------Kidney Damage, Lung Cancer, High Blood Pressure
Hope this helps. That article is good, it lists alternative less toxic paint type/base options.
I do not know of a "less toxic" primer... I just know that I need to have my 3M filter on and adjust it so I don't even smell the paint when can-spraying or airbrushing outside.
Also! Inspiration for a color scheme: Do it for Kane!