we need to be careful of our terminology here to avoid confusions arising. When you say custom, maybe you mean composers tweaked to your own setting? When I describe custom below I am talking about the 20 patterns in the style custom group. My custom is thus the *.rcm file.
All the files you list should load OK, if the 7k follows 6k experience, we need to try a lot of files to find out first. At least the actual important pattern data from composer and sequencer will be intact, even if you have to revoice or re-effect occasionally.
The 6k could not load 5k custom patterns. You had to save all your 5k custom patterns back out as 5k composers to be able to get everything into the 6k. I don't know for sure, but it seems likely the 7k may be the same, but we have to wait and see...
see also http://www.synthzone.com/ubbs/Forum25/HTML/000772.html
because it might also become relevant in some circumstances.