Hi Eric,
You seem to have a good handle on the fact that the tree in its current state isn't much of a bonsai. That's a good thing! I also think that by air layering it (as it seems by the drawing you have planned for it) you will get a great learning experience if nothing else. So go for it!
I'm in FL so the tropicals that I have layered have all been outdoors....
The only thing I could think of that would be a problem for you would be heat...or the lack of. I'm not sure how the lack of heat will effect the success of the layer. I know of Jerry Mieslik, who has extensive experience with growing tropicals indoors in a northern climate. You might want to look him up.
Thanks for sharing,
Ryan
Edit: I wrote my reply before you posted your second set of pics and info. Looks like the layer was a success!