Going with Team Guy. Neji can destroy Temari and Kankuro, and Lee has already shown he can hang with Gaara on his own. Couple that with the fact that if Temari goes down they basically will not be able to get to Tenten(Gaara could but Lee or Neji would likely be in his face the whole time) so she can spam weapons and she actually contributes some decent pressure in this fight. After Neji is done with the other too if Lee is still having trouble with Gaara then Neji and Tenten can help Lee dispose of him.
Team Gai. As others have said, Neji practically stomps Temari and Kankuro. Lee can beat Gaara provided he doesn't use his gates. Gaara needed to keep his sand armor up to fight against Lee and Kankuro mentioned it requires a lot of chakra to maintain. With Neji there with his Byakugan, he would probably be able to see the chakra consumption of the sand armor and Lee can just stick with his normal taijutsu movements. Tenten is useless.