Battery life would be priority for a work phone for me, so I would go with a 5T, Mate 10 Pro, or maybe the Pixel 2 XL. I can get 5-7 hours of SoT on my 2 XL over a full day usually. I'll attach a screenshot I just took today.
View attachment 59749
Plus I don't care much for Samsung's or LG's software in terms of sustained performance and slow support/updates.
AT&T has to sell the phones and the ones you listed they do not sell. As this is a business phone on a business account bought from AT&T.