I'm 9 minutes into the video and it sounds like Vieira has no idea about the MLS roster rules and is replying on Claudio and the staff for that part of the league. That being said, I think we all know that Vieira's is a coach and not a manager. However, when it comes to the technical aspects of the MLS game, strategy, etc. I hope he's ready.
EDIT: Finished the video, Claudio said that all roster decisions, players coming in and out are made after speaking with the coaching staff. They're also looking to build a team that is suited to play against the teams they play more, i.e. Eastern Conference foes. As stated elsewhere on Twitter, Man City EDS loanees are not going to be used to build the roster but rather fill it out if necessary.
Also, we can know welcome French media to growing collection of foreign media to NYCFC press conferences.