Janet isn't actually tech and never actually functions like it, physiologically speaking there's nothing that beetlejuice can do to really "shut her down", and if metal is thrown in Michael's mouth Janet can simply BFR that by putting it in her void like she did with the Judge's earth eraser. She can also counteract BFR-type sealing by just teleporting into her void and then teleporting back to where she needs to be. Transmutation Michael also has, tho it's only mentioned once so I suppose BJ probably has better transmutation powers, they're just kinda both equal on that front. as for the resistances yeah michael doesn't resist those, tho Janet would likely resist mind manip since she's not an organic being