This is a RetroPi based MAME cabinet.  Here's the rundown on my control panel:
  Track ball
  Spinner
  2 4/8-way joysticks
  8 buttons
  4 admin buttons (12 buttons total).
  First question:  I am looking at using Ultimarc's Mag-Stik Plus, with the Ball-Top handle.  It converts from 4-way to 8-way by pulling up on the stick, and rotating.  But, it costs within a few dollars of the UltraStik.  The UltraStik has lots of capability that I don't really think I need.  
  Details:
1) The Mag-Stik Plus does everything I want.
2) Not sure if I can run the UltraStik with Raspberry Pi.
3) If using the Ultrastik, it can connect the buttons, but not the spinner and trackball.
  So, I'm leaning toward the Mag-Stik Plus, and I am wondering if there's something I'm missing?
  Second question:  I am pretty sure that if I use the IPAC2 that it can handle the inputs for everything I've listed.  Do you guys agree?
  Thanks!