Definitely 2.2
Wouldn't use have here. Probably if we used the 2.1 construction it has become So you've finally arrived and the 've has merged with the f and become lost. I also think that US'ns wouldn't normally use that phrase at all
But note: So you've come at last. and not *So you came at last
Pretty much go along with everybody else on 1. I think you've got a good cross section of US'n's usage here.
And Note: The * in my note above indicates "improper" (in the Safiric sense; If it sounds funny the hell with it) usage.
