fusing his main body with the mask i think the jonin take this
Gai > Kisame
Inoichi > Hidan
Darui could hold off deidara
Kitsuchi & Hiashi could defeat kakuzu
Kankuro could hold his own against sasori
Kakashi could stalemate Itachi via Kamui
Wait wait, Inoichi>Hidan?
He uses mind transfer, and Kakuzu impales Hidan with Raiton, which kills Inoichi but not Hidan ._. He's dead
Gai>Kisame? Perhaps, but who says they would be fighting each other? If Kisame were to use 1000 Sharks and Gai using That 1000 punch thing, Itachi simply skewers him with Totska, as he would be standing there throwing punches, or light him up with amertarasu.
Darui? Holding off Deidara? Nah, His black lightning is not enough to hold off the bombs.
:| Kakuzu shits on them together, Kitsuchi uses Earth Style, and Kakuzu simply rips through it with Raiton,
Hiashi has no counter to Jutsu barages or even his threads. Plus Gentle fist may not penetrate domu U_U.
Kankuro gets shit on by Sasori, no explanation needed.
Kakashi can't actually. If he uses Kamui to try and finish him, someone else kills Kakashi as he would need to remain looking at itachi's feet. And not be able to notice other Akatsuki, like Sasori's puppet for instance