Okay, I went back and made some changes to the first round of combat (in the Tarrasque's favor, mostly) and started into the second round. Several people have landed attacks that deal ongoing damage. I believe it's mostly untyped. In the first round, the wizard landed landed Destructive Salutation, which gives ongoing 10 and stuns. The tarrasque failed the saving throw against that, thanks to the rogue. It didn't take any damage from it because of damage resistance, no problem.
The rogue then landed 10 ongoing damage thanks to Deep Dagger Wound in the second round. Right after that, the wizard hit with Disintegrate* which also deals 10 ongoing damage.
1) That's a total of 30 ongoing damage which gets resolved at the start of the Tarrasque's turn. Destructive Salutation's ongoing damage is specifically stated to be psychic damage, but the other two are untyped. On the Tarrasque's third turn, should these ongoing effects be resolved separately for 10-10=0, 10-10=0, and 10-10=0 damage? Or should they be treated as 10-10=0 & 20-10=10? There's also the remote possibility that they all stack and should be treated as 30-10=20.
Another matter of interest is that the Tarrasque used its Fury ability in the first round, and that recharges on a 5 or 6. However, the Tarrasque was stunned on its second turn.
2) Does the recharge roll still happen? If so, the Tarrasque rolled a 6 and, in the event that it shakes off its stun, will be willing to lay a hurtin' on someone. Two someones.
* The rogue landed a critical hit on her first attack which, thank to Triumphant Attack, has made it easier for others to hit. Luckily for the party, the tarrasque actually failed that saving throw.