Don't underestimate their power, there's a reason as to why Kishimoto left them out of Pain Invasion or any battles with the Akatsuki. He knew that Neji would do what Hinata can't and knew that Gai would instantly rush to protect Kakashi, Lee to Naruto.
Sasori gets his puppets smashed by Lee and Neji
Kakuzus masks get smashed and his main heart ripped out by Lees raw strength and blitz speed
Hidan gets decapitated by Lee
Sasuke gets a double whammy from Neji and Lee
Kakashi gets the same
Ay gets speed blitzed by Lee and gets owned like a chump
XD i can't stop loving this.
They dont stand a change against 1 vs 1 against Sasori, they can get pass first senbons/weaponary but rest is too much. Just to say; i believe together they can put up a decent fight against him. By decent i Meant not dying in 6 minutes.
Lee will give himself open for a strike anytime he attempts an attacks on Kakuzu's heart and can't get pass diamond hard skin.
Lee does not use weaponary, but with full intel and a kunai he can decapitate Hidan.
They stand No chances against Sasuke for countless reasons.
Kakashi is kamui hacked. Bit restrict kamui they can make a decent fight against him together or maybe defeat extreme diff.
A is faster than Lee he can't be blitzed, even Lee manages some strikes due to A's linear style, he can't do much against lightning armor and A's durabilty.
I am the last person to underestimate their power here, but those guys are too much for Lee and Neji. The strongest people they can defeat in 1 vs 1 are Darui or Kitsuchi and maybe Kimimaro/Tsunade wo Katsuyu for Neji imo.
Most likely reason why Team Gai was not there is for being a reason why Gai did not go 8 gates and Team Gai generally moving as a Team together.