So, last year a group of friends bought an old rod and gun club in Central New York for almost nothing. It was in fairly rough shape but after fixing the place up a bit, it's a really cool little hangout. For what we used to pay for a fishing cabin once a year, we now have a place all year round. It's essentially a man cave for 6 guys and our friends and family.
So while my friends are doing the smart things and buying all the 'necessities for camp" (roofing tiles, lighting, paint), I'm buying the really important stuff: the games. I already have an Operation Wolf cabinet in place, along with a shuffle bowler, a Megatouch, an Arachnid arcade dart machine, shuffleboard, pool, poker, and ping pong tables, an HD Projector, satellite TV, and two kegerators (sporting some nice craft beer). It's coming along nicely

I purchased a World Class Bowling Cabinet on Ebay. It's a pedestal style cabinet, 33" monitor. I'm thinking of ripping out the board and putting in a PC to run MAME. I'm going to convert the World Class Bowling stand into a 4 player console, with trackball and spinner.
But there's one dilemma: since it's a sportman's club (and because some of my friends are avid hunters), they want shooters. This is not an issue: bought a couple act labs so I can run various shooters in MAME. But they want Big Buck Hunter.
So I bought the IT shotgun, the harness, the PCB, and the hard drive for the system. So here's my dilemma:
1.) I'm keeping the CRT in the cabinet. I need suggestions for, as seamlessly as possible, integrating the 4 player MAME setup with the Big Buck Hunter PCB. I've been looking at a combination of IPACs and J-PACs and a 6 PCB multijamma board (because I may want to add more boards later). I also plan on using an ArcadeVGA. I just don't know what would be best for my setup.
2.) Is there a way I can have the jamma board Big Buck Hunter share the same Player 1 and Player 2 buttons with the same buttons I would use for player 1/2 on my MAME setups (with IPAC or whatever)?
3.) There's potentially going to be a lot of USB connections. Should I use a separate powered USB hub to accommodate all these connections?
4.) Is there anything such as a harness splitter for the shotgun? I would have no issue buying additional BBH PCBs in the future but i would love a suggestions for sharing out the gun between multiple boards?
Any help or background to anything you've done similar would be great appreciated. Thanks!