Another idea, maybe simpler:
FBLauncher.exe gets the remoteHost IP from Hyperlobby, using the IP FBLauncher.exe sends a request to your emu.exe via a specified port, if emu.exe responds then FBLaunch ...
Here is a suggested solution which has no impact to Hyperlobby, no changes to the HL-Code required, only FBLauncher.exe needs to be modified so it could read the launching parameters from HL.