Actually I just went through and doublechecked. Lady Irane is indeed the exception. She has the 'enduring' trait supposedly from her faction, but not something that can normally be acquired by building a custom soveriegn and attaching them to tarth.
The other three have spent only 6 points and as such do not recieve any sort of accomodation for missing the profession. Now that I think about it.. wasn't there a +1 prestige profession? I think these three had that and lost it when it was removed.
Ahem.. in any case three of the four listed are not compensated for the loss, but all of them are built using a non-duplicatable system.
Edit: What the hell? None of the soveriegns are designed using duplicatable methods. *anger*
