I've done some more world building and I think I have my creature's culture mostly figured out. They originally organized based on their location when they transformed, but now consider the group of creatures they're with to be family. The older members of the groups are considered wise elders, and are fed and help around the camp areas even if they cannot hunt. The young, but adult, creatures can all hunt, though if the ladies know they are pregnant, they generally abstain. The children are watched over by the entire group, though most often by their parents or adopted parents if they've transformed.
The creatures form monogamous pair bonds and recognize that incest is detrimental. Since any creatures who are currently members of their group are considered family, if any of their members are reaching maturity they are placed with another group who has a similarly unattached creature. The groups most often meet with those on the edges of their territory, so in time this will not be enough to prevent all inbreeding, but the timeline of seven years after the initial outbreak presents no problems.
The creatures communicate via musical tones, which presents a serious difficulty when they attempt to communicate with humans. Most humans who have been sent into "enemy territory" are deaf, to prevent them from transforming. My group of humans will include civilians, who have not been required to become deaf by any military, but they will be kept inside soundproofed areas and away from any creatures. The deaf humans all communicate with American Sign Language, and some of them know other varieties as well.
The groups of creatures spend most of their time in nomadic pursuits, catching food on their territory and hiding from the elements. They tend to avoid cities, which make them feel uncomfortable, but will sometimes follow food or seek shelter in them. They do not, however, enter buildings. The enclosed spaces make most creatures feel uncomfortable.
Still no name for the creatures beyond the Latin Homo sapiens felinis. In addition to world building for this, I've added another scene to my Camp NaNo and I'm a little sad I have to stop working on it to focus completely on the new NaNo soon. I suppose I had 3 months to finish it and this is just my procrastination kicking me in the butt. Oh well! Maybe I'll use it as a reward for finishing the day's NaNo words on occasion!