Changing open/close button could be done via Python but it would mean messing around with geometry so it would be very specific for that garment. 

You would have to know the vertex numbers to add the polygons that make the connection. Maybe it is easier to build in all the connecting geometry (build with all buttons closed), and make the connecting polys a group per button. You can then easily delete the polygons of the connections you want 'open'. You can do that in the group tool. No need for Python, but of course that action can be scripted.

Remember: Clothify only AFTER you made the geometry changes. The cloth room uses a copy geometry and geometry changes you make to the original may/will not be carried to the copy.