I got my marine to shoot his Gauss Rifle and Marauder's 'nades at the same time by adding the wanted weapons to my Marine (Data Editor -> Marine -> Combat - Weapons). After that I went to edit the Marine's Gauss Rifle (Weapons tab -> Marine - C-14 Gauss Rifle -> Weapon - Options, and unticked "Linked Cooldown").
If there are any better ways, someone should post 'em here or make a tutorial. Hope this helped!
I'm on a page about incorrect corrections, and spent the better part of like two hours trying to get someone to understand that -5^2 = -25, not 25, and then that post had comments get reposted because that group is self sustaining, and that person was in turn trying to explain what I just explained to them. And I'm taking that as a victory
I will be AFK for a couple of days you guys hold down the fort while I am gone. I will be checking in on my phone but that will severly limit me. Be back saturday!