reach xbox one insider question

If you are already a insider, in the program and have the mcc insider on your Xbox, will reach be on the insider game? If so then when?

It’ll become available to play when Xbox flights launch, but we don’t have an estimated time for that yet.
The first Xbox flight(s) might not be available to everyone that’s registered (akin to the PC version), so you’ll have to wait for confirmation.
At the end of the day there’s not much that can be done to speed things along, so just keep an eye on the forums. When invites go out, they’ll reveal everything you need to do to play it.

MCC Insider and Halo Insider are completely different. The Xbox flights for Reach will most likey use a different program from the one used previously. You have to be signed up through this website via your account at the top right, fill out all required details and make sure you are opted in for “console flighting”. Then you are good to go.