Right now it seems like there are only 2 models per each. Last year they had the same 2 models for each phone but then it was divided between CDMA and GSM, however its been proven that the CDMA/GSM versions of the same model were exactly the same as the unlocked GSM model worked with Verizon no problem. A1522 CDMA was identical to A1522GSM even though it said the GSM did not have CDMA radios. So maybe this year it will be the same, maybe not. Till we start seeing them ship we will not know.
http://www.apple.com/iphone/LTE/
The above link has all the info we need, except for info on the 6S models.
http://www.apple.com/iphone/LTE/
The above link has all the info we need, except for info on the 6S models.