Can I put a textured (stucco type) ceiling over wallpaper?
that has been painted over?
Suggested Project Book
I would worry that the underlying wallpaper may let loose or bubble with the addition of stucco type paint. Have you considered just putting a thin plywood or sheetrock over the whole thing and start with a fresh surface?
I agree with the comment above about being scared that the wallpaper having issues in the future.