I know you mentioned you had another frame to make 2 into 1, but figured I'd chime in and let you know I have a couple ATC110 frames, 79 and 81. I got them in even worse shape, but not as hacked up. Just about everything was missing except the engines, frame and front forks. I might have an axle and some other misc
parts. I don't think I had a front fender.
I also have a couple ATC125M's 84 and 85 if you need any
parts from them. One was a hunting machine and the other was torn down by the last owner. Both have the shifting problem that's common on that engine. My plans for them kind of fizzled away so pretty much open to part them out too. Maybe the front fender could be worked into the 110 frame?
Anyway, good luck on the project, most of the machines I ride started out something like what you have.