Studio One Pro Compatibility Question

[gman1951]

Question from a noob in the world of workstation compatibility. I'm running Presonus Studio One 5 Pro in my studio and I want to integrate a high-end workstation and avoid compatibility issues. To give you an idea of what I would want as far as capabilities, under consideration are Fantom 6/7, Fantom 06/07, Kurtzweil 2700, as well as comparable Yamaha and Korg models. I'd like to keep the cost below the $4k mark and might consider used as well as new (although used kinda scares me). I'm looking for advice pre-purchase so I can buy with confidence. Thanks in advance. BTW, I'm a guitarist so not real familiar with Keyboard lingo.