1) Blu ray only supports 50p in 1280×720 and DVD only supports 25 so I’d edit it as a 25fps project or render it out at 25 when you’re done.
2) You’ll need to export it so it fits the media you’re trying to put it into.
3) That nofilmschool.com article is terrible.
4) You can edit AVCHD natively.
5) Shouldn’t matter.
6) I have no idea what that is.