Correct, EC25-A modem for the North American model.
The Global model uses the Quectel EG25-G modem.
Images in Repo
Fixed! The images are now in the repo.
Wireless Carrier Support
To see which bands are supported by the two different models, check out the chart here:
It looks like gpsd has been ported to OpenWRT:
You'll probably have to enable the OpenWRT repos on your Omega2 LTE to install it.
See the guide in our documentation: http://docs.onion.io/omega2-docs/using-opkg.html#using-opkg-switch-to-lede-repos
GNSS with No LTE
Yes, it is possible to have the GNSS receiver and the LTE connection disabled. Just note that the modem will still likely fire up the LTE modem to use cell towers to assist in geo-location.