To include Captain Robau is a gorgeous idea!
And you can include him without troubling the Alternate Universe, simply by setting the story firmly in the main timeline, i.e. with the Kelvin
at Earth in 2233 (so Kirk's mother can beam down to Iowa in time) and not being destroyed.
I like the idea because it sheds light on the early lost era 2161-2245. I know there is a fan fic Star Trek: Kelvin
, nevertheless I'd like to read an official version.
Others pro's include that we could learn more about the two cool aliens aboard Kelvin
(the helmsman and the Cygnian(?) doctor).
/my two cents