How to protect fake suede?

Those sprays should be ok. Usually it'll say on the can somewhere exactly what you can use it for. I had a pair of faux suede boots and I just went to Payless and grabbed some waterproofing spray they sold. It has worked well so far. The one thing I did notice though, and Idk what color your boots are, but I had grey ones and spraying them did make them a tad darker (not too much), so just be aware of that in case.