Subject TL;DR

Getting my RPi 2B set up as a solid travel router. Got a few 2.4 dongles which work pretty reliably so far but decided to grab a 5Ghz capable dongle. Picked up a TL-WDN4200 (RT3573) at Microcenter. Recognized and working through Luci it seems to recognize it has a 5Ghz mode and lets me set up an AP but it is never visible on any of my client devices. Just curious if there's anything I am possibly missing with these dongles that won't do what I want? There was also a Tenda W522U (RT3572) at Microcenter as well that I could get instead of it makes any difference at all.

A side question I had to this on some other sites I have seen them referred to as 'combo' devices. Do they have the ability to run both 2.4 and 5 simultaneously in AP mode or is that just not doable? I have a feeling it is the latter but it'd be cool to consolidate into a single dongle if I can.

Thanks!