In my opinion, I believe Sky should send Henao to the Vuelta and go for (the) 3 grand tour victories.
(Although I still don't think that Wiggo will win the Giro this year)
I would send Henao first to the Giro as masterhelper/lieutenant for Wiggins and let me have a go at it in the Vuelta - and if you would send him to the Tour, he might not be recovered in time for the Vuelta.
You could argue that Uran - being roughly a year older than Henao - deserves a chance in the Vuelta as well (first), but you can send them both and see who is best.
But still if you're Sky, you would be looking to use one of them in the Giro and one in the Tour, and the one doing the Giro most likely will have an advantage.
Now I know ...
.... with the form Porte has this year, you could definitely use him as well (in the Vuelta). But
he will be most likely knackered after the Tour, since I expect him to be able to go for a top 10 place there (similar to Froome last year).
Actually... Sky just has a luxury problem
... let some of these guys go to other teams....