I think it's a very close fight.
Gai is indeed faster featwise, and Kakashi's movements combined with his jutsu will be far more efficient because of the Sharingan.
Tsunade or Base Jiraiya will be put under insane pressure if Kakashi/Gai resort to
You must be registered for see links
(considering the 30 metres distance) and will have to retreat and open up a gap. Assuming that Jiraiya/Tsunade can put distance between themselves and a faster adversary,
In scenario 3 (no restrictions) the big factor in this match becomes
whether Jiraiya and Tsunade get the chance to summon/enter sage mode, and if Kakashi has the genjutsu aptitude to control summons (or decides to use Kamui on Jiraiya or Tsunade) the Dynamic duo (Kakashi/Gai) will be able to stay in the game.
Kakashi's constant success with Bunshin feints on high tier opponents leads me to believe he will be able to create an opening to capitalize upon.
Jiraiya's huge arsenal (even in base) makes him a very dangerous opponent, (and the sannin of course have their summons, Tsunade's healing abilities would indeed be useful)
Could go either way in scenario 1, although i'm leaning towards the masters since Tsunade's feats are overall worse than the other characters in this matchup
