Heh, you are going through exactly what I went through about 2 months ago.
I checked out all of those cards you listed... I wasn't able to get a concrete yes / no if it would be DBDC so I opted to go this route.
Another thing, although not THAT important... The two adapters I use (MikroTik ones) are both 29dBm on the 2.4ghz, and 30dBm on the 5ghz. Most of these DBDC cards are about 20dBm... I'm sure that would be fine for most setups but worth mentioning.
What ever you decide to go with as far as wifi cards go, I am fairly sure you will be happy with the APU2 it self.
The only issue I had is my serial cable is a little bit finicky. To get it to work properly I have to unplug and replug it to make it work. But this is only used during initial setup or when you need a "display" from the APU2 and I will mention I ordered a random one off Amazon not the one they recommend on the pcengines site so I'm sure thats why.
Besides that, a flawless device.
PS : Pick the APU2 model correctly, I do not recall exactly what one but the one with 2 sim card slots, one of the mini pcie slots is USB only or something like that which is fine for LTE but a no-go for a proper 802.11 wifi adapter.