everything about the contract goes through as stated in a ROFR situation (except that you as the buyer are replaced by disney). if the buyer agreed to pay closing costs, disney will step in an pay closing costs...and so on...
I can speak for The Timeshare Store, Inc.® contracts. If we at The Timeshare Store, Inc.® sell a DVC contract that is then ROFR'ed by Disney we still get paid our commission but the the closing company (typically we use Magic Vacation Title) does not make any money on the closing costs.
When The Timeshare Store, Inc.® puts a contract together and uses Magic Vacation Title we use their chart to calculate the closing costs. If the price is such so that the closing costs equal $500 then we write the contract up as such. Now if Disney buys it back then Disney has nothing to do with Magic Vacation Title so they are out. As far as how Disney closes their own buybacks is on them. I am sure they have their own costs associated with buying it back as far as recording, etc. but I am sure far less than the $500.