What was the significance of the ACS module Soap and Roach attempted to get to in the beginning of the game?

If Russia was already in Ultranationalist command, why would Makarov need an alibi to attack the US (“No Russian”)? In ultranationalist control, I’m pretty sure anything the government tells you, you would do.

How in the world would Rojas, the ARMS DEALER, know anything about the “prisoner” situated in the gulags? What was Makarov’s initial plan to deal with this prisoner?