If you want to play with a Core-XY machine, go for it! But I can tell you that you will most certainly be on a the 'Road less traveled'. There was an obvious bug in the Marlin Core-XY code and nobody found it for months. The reason is hardly anybody is doing anything with Core-XY.

If you really want to do it, go for it. But if you think it is a well supported platform, well... Think again!