This is an era I've been interested in reading about, this & the years after First Contact (2063 on).
As it happens, my original pitch was Star Trek: Beginnings, which would've been a multibook series covering the span between 2063 and the start of ENT. But it was wisely decided that that would be far too narrow in its appeal, since it would be too lacking in familiar characters and elements. I was offered this project as an alternative, and after my initial hesitation, I saw how much potential there was in it.
I must ask are you feeling it is a good chance to re-introduce the (oft-maligned) characters of Enterprise? Or are you glad to have many more potential characters in your sandbox?
I'm certainly trying to flesh out the potential of the ENT characters to the best of my ability, but there weren't really that many of them, so the story I'm telling requires adding some new ones, who will hopefully be appealing to readers.
Also with 'exploration' being one of your points, will the novel include still lots of science, or after having done several 'harder sf' novels, will this be more the subtle idea of social and political difference like in your Typhon Pact novella?
There should be a balance of both.