They have completely different vocal ranges. Hayley has an incredibly unique voice. It's almost insulting to her to say that Jenna sounds identical to her.
Plus, their musicianship is entirely different. Paramore has the pop influence, Tonight Alive clearly takes some influence from metal.
Her voice does
sound like Hayley, though. I never said anything about their vocal ranges. I'm not saying either band sounds the same, just to clarify.