The Typhon Pact seems to be comprised of races that have been hostile towards the Federation, though the Gorn seem to be the anomaly of the group as they're not as hostile as the other races have been. It would seem that the Federation is taking the formation of the Pact as a threat, most likely thanks to the Tholian Ambassador, as they're going to attempt to expand the Khitomer Accords. A cold war is the most likely event that will come out of this, not full scale war. The Federation hasn't had a pretty image of late so they can capitalize on any ill feelings any race might have about joining the Federation. The Tholians being a part of this is very strange but it seems to be motivated more along the lines of 'payback' than anything else. If the IRS, Cardassians, Talarians, and Ferengi were not invited to be in the Pact and were as clueless as the Federation, I can see them siding with the Federation and Klingons in response. My guess would be that two of them will for sure, the others will attempt to maintain neutrality.