1. No it doesn't matter but if you are using a xci for Zelda rev1 and rev2 have updates incorporated so you have to erase the updates using update mode. Put the xci as base, then set content to add and then say to remove the previous update.
2.Yes
3. Normally yes, if not is due to their way of scanning the xci. It'll show on the system.
4.Yes
5. Yes, using update mode.
6. N1dus works and SX OS installer works best. You can also split their content with NSCB or 4nxci or make a multi nap Wich works with blawar tinfoil, SX installer and SX is rommenu.
7. That's not how splitnsp works. You can through NSCB but they'll be titlerights-remove nap since I didn't add titlerights-remove restoration yet.
Titlerights-remove nsps also work in atmosphere with the4n patches. For a full configured pack I recommend singularité:
https://github.com/RShadowhand/singularite/releases