This page assumes no previous soldering knowledge whatsoever.
If you want perfect connection of real Wii motes to the Dolphin emulator, you want to pass-through one of the original chips to Dolphin.
There are two chips, the older 4250A-WML-C43 and the newer J27H002. The only difference between those seems to be that the newer version has slightly smaller test pads, but they're pretty small on both versions, so it's not going to make your job too much easier by choosing one over the other.
Both chips go for about $1.3 a pop on Aliexpress.
List of things you'll need for this -
When you're done and you get the USB dongle to show up when connected, follow the Bluetooth Passthrough wiki page.
I will not be wiring the sync button as you can just use the software button in Dolphin when connecting the Wii motes, so essentially just ignore the button on the following schematic. If you want it there you're free to wire it up of course.