Some slice features I can't find

I use slices all the time, but there are some features I either just cant find, or aren’t in Aseprite yet.
I’m just posting this to see which is the case, and if there are any plugins (or even external software) that can do the following:

1- Change the slice border colors of pre-existing slices
2- Copy/paste slices between documents
3- Set unique folders for each slice file to go to, not just all in one folder

Any info would be much appreciated, thanks!