XFI 2.0 is a lateral step or an upgrade from BS3, actually. It is no easier nor more difficult than BS3 - same shit, same designer, some overhaul by FAST after Meaney left.
Regular 4 tooth magnetic crank trigger? Should be easy peasy. I've never set up a trigger for BS3 but $ to doughnuts it's the same as XFI. If you are in a pinch with setup, call Precision/PTE and say *your customer* purchased the BS3 from them and you have the honor of sorting it and making it run. They are pretty good about shooting you in the right direction at that point, although it's been some years since I've done that.
Holley HP/Dominator is the best solution if you want to ditch BS3... but, BS3 is pretty vanilla and simple, if you can't figure it out I do not think you will do any better with a different flavor.