When I first heard about the raid on Manafort’s home, I speculated that the Mueller team had obtained a whole pile of evidence through the CIA/NSA surveillance that was orchestrated under the FISA warrant last year, but couldn’t use any of that evidence in a criminal prosecution because it would likely be thrown out of court. The raid on Manafort’s home may have been conducted to get evidence through “legitimate” means that they already had from the prior surveillance.
I think you are probably correct on that.
Think the house search comes under the fruit from a poison tree problem. If they got information from the intelligence agencies that was tainted from the made up story from Hillary and the DNC, then the search of his house would not have occurred without the tainted intelligence information. It may all be thrown out. Then the collusion case dries up.
The legal term for that is “parallel construction”.