Team should win....maybe? Lol. Namors a badass but if they went straight for the kill they could both one shot him. Nova for Johny or a storm inside Namors brain.
Otherwise, they lose. Storms electricity isnt Thors and Namor is already highly resistant to electricity and he will breeze right through a tornado. Johny has to go all out to hurt him and he ususally wont.
They only win if no morals.
Namor. But........
Vs HT, depending on writer, his fire resistance is ridiculous. He survived the combined assault of THREE Human Torches and was only knocked unconscious.
Vs Storm, she'd have to be beyond stupid to use anything except wind attacks against him and even then, he's a powerful flier and has a chance to muscle through them (and she may wind up affecting Torch anyway). Lightening attacks would be ineffectual because he can absorb and redirect them.