Is it possible and do you plan on adding the correct CoA's for baronies? The random select barony CoA's actually manage to irritate me a bit. Like how can you have The Hague in a game without its iconic stork? Blasphemy! I'd do it myself if I had a hunch of where to start (I did a mod for CK1 once) but all the same, for the sake of flavour you might want to include it in the mod.
Speaking of CoA's, there a few that are off. Particularly the Frisian ones. Westfriesland is pretty ambiguous, but it definately wasn't red chevrons. That one belongs to Egmond (that's 1 barony coa already in the game folder!). It's often assumed to be the regular Frisian coa. After the Act of Abjuration it was changed by the States of Westfriesland to make the squares silver and reduce them to 5, the lions facing left. The current one stems from the 20th century, but is nonetheless probably still the most representative and accurate of Westfriesland's history. The previous CoA's having only been carried on paper because Westfriesland is a non-existant province.
Friesland proper is also rather hard to pin down, but the black paws of the current CoA are definately not amongst the possibilities. Maybe, again, it's from a shire of abbey. The golden lions on a blue field are likely derived from Gelre, which at times claimed overlordship of Friesland, but never had any more luck controlling it than Holland. The blue field could be littered with silver coins, bars, or alternatively golden ones, but the current one was granted by Filips II and has been used consistently since then. This also proves how hard Westfriesland's arms are to confirm. The Duchy coa in the game folder has neither coins nor bars by the way, so it's equally confused.
Ostfriesland used the Dutch Friesland coa, but was not part of the Netherlands when Friesland settled on its coa, so it's wrong. But hey, anything to avoid the multiquarted 17th century county coa am I right?
Gelre's coa is technically accurate, but the Ducht coa probably needs an update. The flowers and bars used alternatingly for Gelre were lost when it was promoted to duchy, so only the golden lion on a blue field remained. The addition of the lion of Gulik was only short lived, so its inclusion in the modern coa of Gelderland is slightly arrogant. In my mod, I used the upper half of the coa of Zutphen:
I hope this will help your project. I might post some more on the baronies later if you'd care.
PS: I seem to have a thumbnail tailing my post. I can't seem to be able to remove it however.