Martin, on the gbatek documentation you cite that the EU version of this game does not have Wifi,
this appears to be incorrect.(to a degree)
the EU version itself appears to have been altered (in a poor way) and reacts differently to SIOCNT state than the US version, resulting in some hangs and issues when SIOCNT state isn't emulated correctly.
However the game does implement the wifi menu, the wifi lobby and all necessary code to play using the Wireless Adapter, so long as you sort of fudge the SIO state,
In the current state of the vba-m emulator, forcing on RFU emulation reveals the Wireless Menu, that by documentation accounts, should not exist.
Currently we fail to establish a client connection to the host due to a missing command, which replicates on the US copy as well.