It is feasible to have multiple sprx running in background.
If the menus are activated with different combos, so only one menu is activated at once, then the answer is yes.
If the menus are activated with the same combos, they will try to compete for memory, screen and other resources, and you may end with a system crash.
Take in count that each resident sprx consume memory and having multiple menus loaded could crash the game if there is not enough free memory (even if there are not conflicts among them).