This will be a very nice quilt. Having "scabbed on" borders for similar reasons in the past, I have a warning for you. Stop your quilting a couple of inches from the edge. Otherwise, your border will tend to be distorted relative to the body of the quilt.
I find it pretty easy to quilt borders on my Janome. Sometimes a friend will LA quilt the body for me and I nned to add borders later.
I have put together supposedly uniform blocks made by other and used the same technique you used. It works.
BTW, I like the pattern of your hot pad, but I think it needed a little more contrast.