Short answer:
Probably not right now ^^'
There are other issues to fix before we can start this and 3ds and wii u friend networks are like separate 🥀

Longer answer I wrote earlier:

From what I saw, like on nintendo back then for some reason, the friend networks for 3ds and Wii U are... separate :/ (except if it changed on pretendo)

I don't know how adaptable this project is for the Wii U network, you can check the code yourself if you want, but feel free to give ideas of how we could make this possible!

Some of 3ds-rpc code might be reusable too

We used to recommend people used the RiiTag project for Wii U support, however it seems like that project is dead atm.

RiiTag: https://github.com/RiiConnect24/RiiTag-RPC

https://www.reddit.com/r/WiiHacks/comments/1ih0g5f/what_happened_to_wiinertag_riitag_dut/