Hi Michelle, I hope this helps, good luck! https://home.howstuffworks.com/home-improvement/home-diy/painting/paint-over-wallpaper2.htm
Should be removed. Ther is always a chance the moisture in the paint can cause the wallpaper to separate or bubble. Also seams may show and will be a pain to remove in the future.
While you can, in some instances, I wouldn't. Eventually it will bubble, pucker or peel and then 100 times harder to remove. Do yourself a favor and remove it now before you paint.
I wouldn't. Having dealt with someone else's painting over wallpaper, and the horrible pain of scraping, steaming and cursing it off for days, I would never do that for someone else to deal with.
Use oil based paint. Do a test area to be sure maybe a few square feet to see whether the paper reacts badly.