#1
for each key of harmonica I would use? For Bob Dylan and Neil Young type stuff.. So far all I know is to capo the 5th fret when using a "C" harp, and for not using a capo, to play a "G" harp.
#2
That's not really how that's gonna work. You need to think about the key of the song. If the song is in G, with a G chord as the tonic, the main resolving chord, you'll use a G harp. If you put the capo at the fifth fret, and play the exact same chord shapes, your G shape will now be a C major chord, meaning you'll use a C harp. So you need to learn to identify the key of the song, and what moving up your capo does to change the key. The key of the song will match the key of the harp.