This may not be something that will cause any issues to FC Dallas in 2016 but it is worth pointing out for any future FCD 2/B/whatever team that could end up in the USL. According to a USSF policy that came down this week, USL teams owned by MLS organizations will not be allowed to compete in the 2016 Lamar Hunt US Open Cup.
"Any Outdoor Professional League Team that is majority owned by a higher-level Outdoor Professional League Team shall be ineligible to participate in the Open Cup. The Open Cup Committee shall review and determine team eligibility annually pursuant to this provision and report its decisions to the National Board of Directors." --USSF bylaws
We don't have an official word as to why this change came down but it is now a new policy that was passed in September. I would imagine this comes down to teams not wanting players to be Cup-tied. I know Oscar Pareja made sure that Danny Garcia wasn't Cup-tied with Arizona this past year.