Second device is RM-984 which was revealed by Adduplex data to have 5-inch, 720p display and we reported some more info about this possible Lumia 720 successor. It has a late August time frame for announcement, which matches to what we reported from our sources.
RM-1028 is not known yet and it will also be released along with the Lumia 720 successor as per the schedule shown above. RM-1027 is the China bound Lumia 636 and RM-1030 is Nokia XL, so it will be interesting to see what RM-1028 actually is.