Honestly I couldn't figure out how to properly work them all. I just renamed things in the files. The main file you'll be working with is dosboxWC_single.conf, and the line:
loadfix -1 WC1
just change it to loadfix -1 WC1 Origin (case sensitive) and debug mode is enabled, and -k after Origin (Origin -k) for invulnerability.
All I could do to figure out playing the secret missions was changing the lines to
loadfix -1 sm1 and loadfix -1 sm2 when I wanted to play them in order.
Bringing in pilots to them is basically just in the gamedat folder so just lead to that folder when the time comes.