Luna-App VS sys-botbase

This one downloads someone else's island to your Switch. You can effectively make an exact copy of their island, and then you can replace your local island with a copy of that island. This means if you found an island you really liked, you can copy it and make it your own. This even works when visiting someone else's island over the internet.

I'm really not sure exactly what you're looking for, but here's Luna, a homebrew program that can dump Dream Islands you visit to storage, where you can later use NHSE to copy whatever you like to other islands.

It's certainly possible - maybe even probable. I've found this program you can run on hacked Switches to allow preprogrammed inputs. This is useful for Tool-Assisted Speedruns (TAS), which can press buttons faster than any human can. It's possible that the same technique could cause Animal Crossing to glitch out.

Well for a save editor that you can use in game you can always try using the sys-botbase ram edit function found in NHSE or you can use ACNHPoker both of these allow you to edit the save in game though they do require an external device to run the editor on.

You can also use sys-botbase if you're running custom firmware to do everything via software, and hook directly into the game with other repos using this module

All you really have to download onto your switch's SD card for ACNHSpawner is sys-botbase (https://github.com/olliz0r/sys-botbase/releases)