Amazing war that could go either way, but I slightly lean towards Carbajal, particularly since a past-it version on his last legs still managed to find a way to stop Jorge Arce in a fun war.
I think Roman would be ahead on the cards in a great fight before Carbajal lands a bomb out of nowhere and ends the fight. Carbajal could occasionally be out-boxed, but, if you went to war with him (as Gonzalez is likely to do) it could be lights out.
Jacob Matlala was someone that overwhelmed Michael Carbajal on the inside and never stopped coming, ultimately beating him. I can see Chocolatito beating Carbajal in the same manner.
From a prime against prime point of view I have to go with Gonzalez. Even in his prime Carbajal got hit too often. I was a huge Carbajal fan and I am relatively neutral about Gonzalez but I think he wins a decision. I'm saying 116-112 in a fight close through eight rounds. At that point the attrition wears Michael down and he loses the last four rounds on the cards.