new articulation

[James E. Bailey]

Hello, I'm transcribing some organ music and there are a couple of  
symbols that are used rather frequently, and I was wondering how  
difficult it would be for me to try and create them myself.

First, a bracket, either above, or below a note, on either the left  
or right side. (I just realised that I didn't scan the version with  
it on the right, but that occurs too.)
And second, something similar to the figured bass extender lines, but  
for fingering, and not connected. I suppose I get that to work with a  
clever assortment of markups, fingering, and script overrides, but  
I'm looking for suggestions on how I could do it better.

Next, a slash that occurs either in the staff, or outside. I've  
strung together a series of overrides that gets me the one in the staff:
{
        \once \override Voice.Stem #'stencil = ##f
        \once \override Voice.Beam #'stencil = ##f
        \once \override Voice.NoteHead #'stencil = #ly:text-interface::print
        \once \override Voice.NoteHead #'text = \markup \tiny "/"
}
I've done similarly for the one above the staff, but as previously  
said, I'm looking for ways to do this better:
\markup \left-align \rotate #330 \bold \tiny "/"

Any help or tips would be much appreciated. Thanks!