Are investigations by the Hill interfering with on going LEO investigations?
The idea that Trump would be investigated for his "go easy on Flynn" remark (if he even made it, Comey is the only person who was there to hear it, and Comey is out to get Trump) is absurd.
The entity that "goes easy" is DoJ, not FBI.
It is also an absurd argument that Trump fired Comey to stop an investigation. Firing the head of the FBI stops ZERO investigations. In the Holt interview, Trump said he saw a downside in firing Comey, it might case the investigations into Flynn, Manafort, and other members of the campaign to take longer.
I don't believe any entity is looking into the accusation that Trump abused his power / obstructed justice by his Flynn remark or by firing Comey. The Senate won't be stepping on Mueller's toes, and the FBI didn't have any investigation open v. Trump when Comey was fired.