What the, where'd you hear that?
Not that I know of. They are the rarest things so you just have to keep trying. Also, you can get dupes.
You have to go to a stable that has customization options. Not all of them have it. I think Highland is one that does. There will be a person standing near the horse stalls who can change the look of your horse and change gear for it.
If I did the first bit of DLC, and now I'm into the second (I think something to do with the Champions?) after doing the one-hit-kill shrines, what is there after that? I think I need to do some more of the actual game too.
The locations match up very close to the Ocarina map - Castle Town (only the fountain is left), Temple of Time, gate to castle, and the castle (Eastern Abbey).
Do the other landmarks that we have confirmed to exist in the past show up in a relatively similar fashion (Lon Lon, Earth Spring, Skyloft Temple) with respect to map placement?
Lon Lon is in Hyrule Field - look on the map for the Ranch Ruins. It matches up. The Forgotten Temple was probably part of Skyloft. It has the Loftwing sculptures and the large goddess statue. All the springs in BotW look almost identical to their Skyward Sword counterparts.