Unlike last year, it appears JP has no problem with them tweeting during the season this time. And there are a lot of alliances seemingly to be revealed. From what I gathered from SS:

Joaquin and So
Joaquin and Rodney clubbing together
Carolyn posting a picture about unity and So sending <3 smilies back.
Jen and Shirin. Jen talked about how much she missed Shirin.
Jen and Joe. They arrived at the same airport from filming
Jen, Joe, and Mike

Then there's the superfan connection on twitter with Nina and Max but that may not pertain to if they aligned in the game or not.

From what I am gathering here, Jen and Joe are not on Mike's tribe. Rodney and Joaquin are not tribemates either and neither are Jen and Shirin.

I'm going to assume that Joaquin, So, Rodney, Carolyn, Jen, Shirin, and Joe all make the merge here. Though I think with So's two alliances, it would appear that they already have half the tribe so they look to be going to the merge. And then take in Rodney and Joaq pulls him in. Jen and Shirin seeming to be that close meant they had to spend more than 6 days together so they either spent a lot of time at Ponderosa and/or were close on the island so I'm penciling them post merge as well. And given the airport tweet that should put Joe in as well. Mike could still be out pre-merge as he, Jen, and Joe(or one of them) could have ended up on the same tribe post-swap.

It would appear these are the alliances for each tribe
So, Joaquin, and Carolyn
Jen, Joe, Hali, and Vince
Rodney and Kelly(he wants to align with the older women), but I see him on the outs after Dan(who clearly looks like a early boot) and avoiding TC until the swap, which probably saves him.