Maybe a phablet and a "mini", lower resolution device?
higherpurpose's point is very important, regarding which is your target market - it's VERY different to develop targeting the U.S. than, say, Latin America.
Edit: I see your company is focused on managing "street crews" for campaigns, I guess first world then :)
Apparently the best-sellers over there are:
- Samsung Galaxy S III (> 30 million sold)
- HTC One
- Motorola DROID
I second higherpurpose's recommendation of a Motorola Moto G (maybe instead of the DROID).
I'd choose a 320 x 480 pixel device like Galaxy Mini 2 for South America, and maybe a 240 x 320 device like Galaxy Pocket which is the default "free" phone over here.
Or, for the Indian market - I've heard they use a lot of local and Chinese brands over there, not necessarily lower specced but I've read about a lot of Mediatek-powered devices.