I love your optimism regarding Froome, but seeing him ride like he has since 2011, especially his bizarre accelerations on Ventoux, I'm not a believer. A pity, because he does seem to be a genuinley likeable person.
About the only Colombian I can see riding for the British contingent would be Henao, as he'll be under contract to Sky next year. Though, even that would be doubtful, as the current crop of riders, especially the large contingent coming from Corti's Colombia team, are fiercely proud of their country, none more so than Uran.
By the way, if the Italians and Swiss do turn up in Lombardy for this year's WC then I'll have put my mortgage on the entrant from Tuvalu taking their asses to the cleaners - the Worlds are in Florence / Tuscany.