When data integrity is clean, I am not able to duplicate what you are running into with the disallowance of editing Control Account Sets, when all 6 of those files are deleted. If you have renamed/deleted all 6 of those files yet still continue to get the message regarding posting journals still existing, I question that your data is clean.

Just to re-iterate, these are the data files that should either not exist or have a file size of zero - to allow editing control account sets:

ARPOSTA, ARPOSTC, ARPOSTI, ARPSTEA, ARPSTEC, ARPSTEI.