[sciurius]

is there an intended way to escape the single quote to have it displayed as a normal character?

You can put a backslash in front of it:

{start_of_verse: label='<span color="blue" weight="bold">B\'</span>'}

Note that this will yield B’ (a curly quote). If you really want a prime symbol, use

{start_of_verse: label='<span color="blue" weight="bold">B\u2032</span>'}

(This actually should go to the ChordPro forum, I think)