As nice as Dolphin would be, I have to agree with the idea that the CPU is just too slow to be of real use for it. You might be able to get something like NSMB or some simple Gamecube games running OK, but most stuff is going to be very slow.
The extra cores don't really help since you can only split the workload over so many threads at once. If you keep adding more it doesn't help past a certain point because you still have to wait for other tasks to finish before you can go on.
Performance would be very close to the Athlon 5350 since that is the same CPU core the XB1/PS4 are based off of. In benchmarks it only comes up a bit under half the speed of a real Wii:
https://www.anandtech.com/show/7933/the-desktop-kabini-review-part-1-athlon-5350-am1/4