For option A you would cut the Sheetrock in your bedroom to access the pipes. This way you can get away without damaging the tiles. I like this idea the best.
For option B you have to check local codes. Here you have to have at least 3/4 to your last fixture which means you can not tee off half inch for a toilet. It's also going to look pretty tacky having the copper line running out of your vanity and along the wall. It will work fine however. Sealing the current hole can just be done with silicone if it's going to be hidden. I don't know how you would cut the old line out and cap it though.
I've never even heard of an insulated toilet, some of the toilets in my house date back to the 20s and I don't think I've ever had a problem with sweating causing any kind of damage to the walls or floors.