Hi J., my name is N., and I do Parent Coaching, having 30 years experience working with children. I have studied early childhood development, and done quite a bit of research on brain/muscular development. To keep this brief:
As myelin is laid down in the brain, different parts of the body develop control and coordination: first comes the head and neck, then the shoulders, arms, torso, legs, etc. One can see this, as the infant grows: first they can only hold their head up, then reach to grab things, etc. At around 5 months old, because the torso is myelinized, they can sit independently, and so on. The point of this being, that by 12 months old, they have complete control over their muscles, including their sphincter (anal) muscle. I have seen children as young as 14 months old use the toilet! Please feel validated that you are way ahead of others, by recognizing her awareness of her own body!
My suggestion: keep it up! If you pass up this "window" of development, and return her to a diaper, you are doing her a disservice. She is telling you, showing you, that she is ready: follow her lead.
The toilet: have both available--let her choose which one she wants. This gives her power, and control in an area that she should have power and control in.
Nap/night-time: this may sound strange, but, again, let her choose, as long as you can live with possibly changing the bed--in the beginning. From the sound of it, I wouldn't anticipate this happening, and if it did, it wouldn't be for long.
good luck!
N.
A little about me:
I am co-owner of a parenting business: www.parentandchildtogether.com where you can read more about my credentials there.
I am the very proud mother of 2 children, ages 24 and 22.