Also, you might want to go back to crusaders_unit_prod11.txt (column 50) and enable some crudade units for the Sicilian.

If I understand correctly:

The AI characteristic (ie CATHOLIC_CRUSADER_TRADER) will effect how often they use crusade.

The AI build probability (ie CATHOLIC_CRUSADER_TRADER(119) ) will effect how many crusade marker they will build. The greater the number, the more often Ai will consider to build.

For crusade units (in column 11), you will often see the negative number in the Parentheses. I forgot what the Devs called (something about short list), but the units with nagative number will always be chosen. The lower number, the more often. You can make any unit appear in the crusade by adding in column 11 CRUSADE(##).

To make crusade spawn with more units, I think you will need to reduce the training cost.