Working around wireframe Issue
I found that I was having an issue when I opened Kit in Maya on a different computer and only the wireframe was loading, and no matter what setting I had it on, it didn't seem to load the lambert material.
The first time I came across this problem I opened an older edit of Kit and worked from there - I had to redo some of the work I had already done but the material loaded on the older version.
However, when opening the most recently saved version of Kit today, it again didn't have any material, and when I tried to add new material, Maya would completely freeze.
I found that after restarting the computer and deleting my history, that I could assign lambert as the material again. From now on, if I have the wireframe issue again I will delete my history and re-assign the material to my model.