My answer to this is very easy, pick the one or two exercises you prefer the most and do them.
Should I be choosing exercises that target all ranges of the bicep?
The elbow flexors do not display much stretched-mediated hypertrophy, most likely due to the sarcomeres work on the plateau of the length-tension relationship even when muscle is stretched, so if you prefer just a simple dumbbell bicep curl that does not work the biceps in the stretched position this will be ok.
How often should I train biceps?
Well the biceps is a fast twitch muscle with very high voluntary activation capacity, which means it is damaged easily and may need to be trained relatively infrequently or with lower volumes.