There are other factors besides just a modem that need to be present and enabled for the rom to work.
If your flashing through odin I would be careful, I would flash through recovery and make sure all the mount points are correct first. The device SHOULD(in theory) not brick - since they are in a nut shell *the same*
EFS partition should be fine, your not touching that UNLESS you flash a modem, if you retain the stock modem and do not flash a new one you should not have to worry about your EFS.
Modem's in my opinion are something that should not be flashed again and again. Flash one and leave it, less likely to corrupt the EFS.
You'll need a kernel as well for LTE, i supposed the stock 7105 will work, because the bands of the modem are defined in the modem.bin.
I'm about to flash omega 7.1 on my 317, I've copied over all the needed files, and edited installer NOT to flash a kernel or modem. So It should work with flying colors