Seeing as how Terminals haven’t been shown off yet it’s led me to assume we won’t be getting the traditional terminals (if they’re still in) done by Sequence.
There’s not much story background to cover that isn’t already addressed in good detail Halo 1-4 that would be necessary for Halo 5. Having terminals based on Blue Team only would seem rather redundant as people new to them would get around to liking them by the end.
Having them making a self contained story about Blue Team as an “animated series” makes the most sense for Sequence.