I was able to successfully launch BullyMP.exe , however the game seems bugged as it won't let me click on anything. Keep in mind that Bully itself runs flawlessly through Steam Proton 3.7-8. My xbox controller even works with the game perfectly.
Motherboard: ASUS M5A97 R2.0 AM3+ AMD 970 SATA 6Gb/s USB 3.0 ATX AMD Motherboard
CPU: AMD FX-8350 Black Edition Vishera 8-Core 4.0 GHz (4.2 GHz Turbo)
GPU: GeForce GTX 1050 Ti
Driver: Nvidia-driver-390 (Open Source)
RAM: Corsair Vengeance 8 GB (2 x 4 GB) DDR3 1600 MHz PC3 12800 240-Pin DDR3 Dual Channel Memory Kit 1.5V
OS: Ubuntu 18.04 Bionic
Any info on how to get Bully MP working would be greatly appreciated.