Yep, those two regs popped immediately to mind and I believe a case could be made for either or both. Could possibly toss in 91.11 for good measure as well.
§91.11 Prohibition on interference with crewmembers.
No person may assault, threaten, intimidate, or interfere with a crewmember in the performance of the crewmember's duties aboard an aircraft being operated.
Harassing a pilot over the radio can be construed as interference in my book.
He definitely did not provide any real assistance and possibly could have caused harm by telling the Arrow pilot to raise his gear and flaps and later to slip.
At the same time, I cannot believe that the Arrow pilot actually went along with the nonsense.
I also can't believe that tower allowed all of it to happen.
An all around messed up situation.