I believe that many mosques in the US are owned by the Muslim Brotherhood or organizations under their control. Will this cause them to be seized or frozen as assets of a terrorist organization?
I guess that would be at the discretion of the DOJ. I would think that they would want to infiltrate and gain cooperation among insiders. The DOJ will have ability to conduct surveillance and their banking transactions/activities will be impaired or entirely halted.
This will have a positive effect if this thing is played slowly. The MB and their sympathizers have to know that they are on the defense. There will be a spirit of fear, paranoia and suspicion at the mosques and various organizations. They will be blamed for terrorist attacks. and the leftist media and pols like Keith Ellison will have to be wary of cooperating with them.