I don't know if this model converts that smoothly to treadle. The potted motor on these is proably hard to find, but if I ever found the parts I would do go for a rewiring and restoration. It is a bit of a hassle, but it's just sloppy work converting it to a treadle just to avoid doing it properly. This is a model where the motor and light works superbly. I guess if a motor comes along there's a good chance it hangs on to the rest of a 101. Would a leather belt easily fit around the hand wheel, will the bobbin winder work? It might work as a treadle.
The 101 is so rare here, I shall probably never see one, it was only made in the US factory. It always get's my attention when I see it. I have a 201, it has a similar drop in bobbin case and rotary hook, it can quilt with out problems. It not a favorite among quilters like the 15, but last couple of years I have come across people who have exclusively set up a 201 for free motion quilting, another use it only for free motion embroidery (with out hoop). I have managed to free motion and get nice stitching, I'm not very good at it, but it's all about tension and even movements. Originally it came with a feed cover plate.
For the cleaning; the shellac can handle a wipe with a damp cloth, it's a common advice for shellac finish wood furniture. The trick is to wring it well up and not leave any dampness on the surface. If you find a bottle of resin type car polish it will likely shine it up almost like new again. You can't remove surface scratches or wear, but dulless and grime be will improved upon.
I'm just thinking out loud really, the 101 is a model that's caught my attention.