I hope I'm able to help. Maybe someone else will weigh in too and see something I'm not thinking about or have a fix they've found successful.

I used Repetier a few times with my RAMPS 1.4 board so I know it's compatible with Marlin at least. If you ever want to upgrade to a really, really nice slicer that's blazing fast, has great supports and a beautiful preview, look at Simpify3D. It's about $160 but it's worth every penny. Some of the guys here turned me onto it and I didn't want to spend the money. Man am I glad I did. For over a year I used Cura, Kisslicer (one of the cleanest slicers I've ever used), Slic3r, Pronterface, Skeinforge (hard as hell but powerful like no other), Repetier and a couple of others. I tended to wander back to Cura mostly. Kisslicer is clean but won't connect to the printer directly. You have to use an SD card with it. Of course all of those are free. There is something, well lots of things, nice to say about Open-Source software. But sometimes a team of developers who create things for profit have the resources to create something truly outstanding. I feel that Simplify3D is one of those. And no, I have no affiliation with them...lol... I just like telling people how much I like it.

Let me know how the tests go.