Use WiimoteHook or WiinUSoft to pair wiimotes with MS stack (those programs made it easy to pair wiimotes without using a PIN since every wiimote has their own PIN based on their MAC address or serial number if i recall), after the remotes are paired and connected, close WiinUSoft or the cmd window if using Wiimotehook. Voila! Your wiimotes should appear in Cemu, also since they are already paired (you can check it out in Windows Bluetooth settings), your wiimotes will automatically connect to your pc as long as the BT stack is on and within range just like a regular Wii or Wii U.
P.S. When you select your wiimotes in cemu their LEDs will turn off, don't worry that's normal! It doesn't mean your wiimote got disconnected. The Wiimote input API is still in its early stages, so expect some issues here and there, but here's a bulleted list of the issues I found so far:
Bulleted list of things that are not yet working 100%: