Hey,
I'm slightly hurt that I did not see Linux servers from the get go, as I thought Unity was this cool engine with a single click build option for Linux. Anyway, of course it is manageable to run it on Linux with some quirks, thanks for even providing server files though!
You need, as usual, to use wine.
But as it seems that the server won't run without opening a window, you also need to install xvfb-run.
And then you just start the server with "xvfb-run --auto-servernum --server-args='-screen 0 640x480x24:32' wine BCoF.exe -batchmode -nographics -server"
and voila, the server runs!
I did however notice a base cpu usage of 40% (of a single core on a 4Ghz Xeon) on start of an empty server, once map change occurred it went down to 9-10%. Not sure if that's normal or a problem generated by not running things on Windows. Ram usage is 4,7GB.
Have fun!