it really depends on the size of the fish tbh. a fully grown severum is a very chunky and powerfull fish to have and against an angelfish there would be only 1 winner if it got a bit rough in there.
it may work, it may not but i would be more concerned about the gouramis as these can be nasty fish at times.
Being is that a Severum can get to be the size of a dinner plate, I would consider keeping them with fish closer to their size. I can see a severum destroying everything you have on your stocking list there, depending on the size of the tank. Wht size is the tank in question and what do you currently have in it?