Without a hindsight, I'd certainly sympathize with a revolutionary forces, embracing best ideas of the Enlightenment (as imperfect we may see them now) against an imperial power. I'm still not sure what my position would be with a hindsight.
I'm not sure--I would be vehemently opposed to integrating the colonies in any way into parliament, because that would prolong slavery. I guess I would, given that the colonies staying as mere colonies in the long term is unlikely.
Why do you say that?
With the colonies remaining loyal, slavery would likely be abolished no later than 1833, as in the rest of the British Empire. Unless there would be a provision to exclude some American colonies (the South), like there was a provision of exclusion
"of the Territories in the Possession of the East India Company," the "Island of Ceylon," and "the Island of Saint Helena", and these exceptions were abolished in 1843. I really can't imagine London retaining slavery just to please a couple of colonies. Actually, I wouldn't be surprised to see abolition process speeded due to this.