I have been in good contact with one of the professors, so I got some feedback from the officer.
She said very clearly in the email, that MIT admit on a ROLLING basis.
As far as I know, the committee make all the decisions. Professors rarely write back unless you get admitted. I don't think there is this second round. As my target professor told me "if you get admitted, we can continue this conversation". Certain professors surly would have huge influence on the committee's decision, but it is mainly done through the committee. The so-called second round, where you need find a RA or TA to get funded happens after you get admission.
I assume that MIT would let us know before 4.15. Let's just wait and see...
Good luck everyone!