#1
This is a huge noob question, but does a 24 fret bass guitar have a 35" scale neck, or not? How does it vary between every bass? How is it labeled?
#2
Scale length is determined by the vibrating length of the string, not the number of frets per se.

Its the measurement between the bridge and the nut.

short = 30"
medium = 32"
Standard = 34"
Long = 35"
Extra-long = 36"

And a 21 fret bass can be a standard scale and there are rare 24 fret short scale. So it does vary between manufacture and bass model.