This is weird, if I put it into the empires roster, it works with no problems!
EDIT: I solved it!! The problem was I needed to add the animations tables from this table "Culture_to_battle_animation_tables_tables"
and then change the faction from empire to bretonnia like this.
The crew is for the extra crew not operating the machine while great cannon is the 3 man crew shooting. After I added this everything works fine!
Working unit in action
Maybe this table is worth mentioning in the tutorial? If people need to transfer a unit from another culture