In hindsight, I think I am wrong. Also your pics suggest more water going down your little timber creek than a 6" pipe could convey.
While your 2-acre pond is surviving big rain events with a 6" outlet, it has a large storage area. For every foot the water level rises, your pond has accumulated 652,000 gallons of water. The main outlet then passes that water over several hours or days.
If you build a tiny dam on the hill slope, your new pond will have very little storage area for rising water.
I believe your trade-offs would then be building a higher dam with more freeboard and more storage space, or adding a second 6" outlet pipe for the tiny pond.
Your distances and local conditions will control your final solution.
(Hope that makes sense, you have a slightly complicated problem that I have not answered well.)
