We got it!!! Finally, after two and a half loooooong days, I understand predicating demonstratives. Ba Mwiinga finally told me this morning that he thought I was deliberately not getting it, and I think he actually meant it! That kind of put a fire under me and made me put aside my stubborn streak and just try a different way. And it all finally came together, and he said, "Now I can sleep tonight!"
Hope you all have some lightbulb moments of your own today!