24) How were the bishops at Hippo and Carthage able to determine the correct canon of Scripture, in spite of the fact that they believed all the distinctively Catholic doctrines such as the apostolic succession of bishops, the sacrifice of the Mass, Christ’s Real Presence in the Eucharist, baptismal regeneration, etc?

Mushrooms?

They were wrong about the Old Testament canon, apostolic succession of bishops, the sacrifice of the Mass, Christ’s Real Presence in the Eucharist, and baptismal regeneration to name a few.

They are irrelevant, immaterial and incompetent to Bible Christianity which rejects them, their beliefs and their canon.

Moreover, the Question is poorly constructed. It is a hasty generalization fallacy to suppose one right decision indicates all their other decisions are right. (And in this case, there wasn't even a right decision!)

__________________
The times of this ignorance God winked at; but now commandeth all men every where to repent:

Behold, I stand at the door, and knock: if any man hear my voice, and open the door, I will come in to him, and will sup with him, and he with me.-kjv