Excellent idea! However, I think the number of possibilities would probably not be all that much more than the number of compounds because you don't need all the possibilities, just all the unique ones. So LiTiMnF6 will also cover Li, LiTi, and LiTiMn. I.e. the many-element system names will cover many of the binaries, ternaries, etc.
The autocompletion is a very nice feature from the user's point of view, so I am glad that you can see ways to improve it. Thanks!