Yep, those could work. The Glutton/spitters would have to be out in a large open area since the model is so wide. I was also thinking of the abomination being great for a boss fight after you mentioned it as a spitter. I also like the idea of spitters sometimes encountered at street intersections as somewhat tough non-boss enemies.
And harvesters could be the general term for all of the creatures. Zombies would always be called harvesters, but other things have their special names as well. So there's regular harvesters (or lesser harvesters), and then there's hounds, crawlers, flesh beasts/brutes, stompers (I like how that name differentiates it from the mountain giant), and spitters (Glutton being a boss spitter).