Outcome

In the picture above, you can see the handle in various stages of the process. From left to right: clay model, (light orange) plastic casting directly after removal from the mold, (blue) plastic casting after using a dremel, (green) plastic casting after dremel and sanding.

Below are some pictures of the silicone mold and molding process. Unfortunately, I ran into trouble with the flap on the inner edges of the silicone mold that would create the crevice for the pot to be inserted in. When I was making the second half of the mold, the flap ripped in half, and after the blue plastic casting, parts of it ripped off completely. This led to a pretty messy crevice that required a lot of work with a dremel to get it to a usable state, and even after that it doesn't look that clean. 

Here's what the handle looks like directly after removal from the mold. As you can see, the crevice is not in great shape and would be unusable as-is.

Here are some pictures of what the handle looks like after it's been cleaned up. The picture directly below of the green handle is after both sanding and using a dremel to clean up that area, while the blue handle is only after using a dremel.

Unfortunately I also ran into some issues with bubbles. Upon first inspection, the castings looked smooth and bubble-free, but sanding/filing/the dremel really exposed the bubbles beneath the surface. I stopped sanding in some areas for fear of exposing more. If I were to do it over, I would definitely have used the vacuum. 

Finally, some pictures of the final product (the green handle)! Also, some pictures in context with the instant pot. It would be best to use two handles, although I've occasionally gotten the green one to pick up the pot by itself.