My two friends use the 3rd option and can get it to work. However, when I put in the -dev command, I can see and play (in skirmish) the games but can't join them.
The only thing that they said could be an issue (and I'm not sure AT ALL how it could be) is that in their shortcut to RelicCoH.exe, it has quotation marks. Looks something like...
Mine, however, when I try and place the quotation marks into the line and hit apply, they disappear as if they aren't needed and the computer automatically removes them.
The files I (and everyone else) have located in the Data\Scenarios\MP folder are...