Overcomplication is bad. It looks like this thread is coming down to the inevitable "how to herd indie traders towards corporations". Well, you won't be able to do it by contracts and whatnot, because no matter what you do your faction won't be able to be online 24/7 and enforce it. Most people just won't care.
Just give corporations cash incentives on cargo that is their speciality, and cash deficiency on cargo that they don't ship = promoting both adopting corporate IDs and trading in RP cargo in them. While freelancer, indie trader etc. ID would simply get no bonuses or deficiencies. This of course involves FLHook coding, but yeah..