Droop travel is no problem, the problem with 16's is that you have to use a softer spring rate to get the same ride height (maybe too soft) and you might have issues fitting the shock and shock hoops under the hood.
We don't mess around with 2" shocks on fullsize trucks at all, you're giving up a lot of performance compared to a 2.5". Plus who knows what the valving is and whether it has the hardware for the coils.
And I know FOA had a lot of quality issues early on. I'd keep looking, nothing wrong with trying to find used stuff cheaper but don't settle for less than 2.5" shocks.