It looks like you won't have to wait long for those two upcoming Nexus phones.
CNET has claimed Google plans to announce both Android devices later this month in San Francisco. The launch event is reportedly scheduled for 29 September. That's the same release date pegged by MKPost, a Korean website site that also notably predicted the launch date for the first Nexus 5. Keep in mind nothing is confirmed as of yet.
Current word on the street is that LG made one of the two Nexus devices. It has a 5.2-inch screen and a polycarbonate shell. Huawei reportedly made the other phone, giving it a 5.7-inch screen, fingerprint sensor, and giant camera module on the rear. While this is Huawei's first time doing a Nexus, LG of course made the first Nexus 5.
It's unclear how much these new phones will cost, though everyone is expecting them to be relatively affordable, especially considering low-cost Android phones tend to see better adoption. It's also unclear if they will showcase the latest version of Android, called Android Marshmallow, though we can assume that'll be the case.