Heyo!

I‘d suggest you to not run Edo Itachi and Shisui at the same team first of all as main team. Naruto Six Paths works perfectly with Itachi edo and you could run:

Naruto - Itachi - Sakura Summer - Earth Main

Naruto - Itachi - Killerbee/Madara - Wind Main/Earth Main

Naruto - Itachi - Kakashi Susano‘o - Earth Main (Some Gnw Support Team)

You can make infinity combinations, but as main team I wouldn‘t suggest them both. However, it happens to be decent as a arena team.

Using him as fire main is a decent option, but I‘d prefer earth main, especially with that Itachi Edo Passive reducing ninjutsu received damage by 50% twice each round.

It‘s a solid team which also works as well, try out and see which one you like most

You're welcome