Hello. After completing the Vault of Braccus and getting rid of the collars I ended with the SJ of Rex's former friends . Question: Is there any repercussion for eating these souls in order to replenish source points?

Really? There are plenty of walkthroughs that says what to do, why people want to be spoonfed on every corner?

There is no repercussion besides not being able to use them for a certain quest. If you need to replenish source points, look around some more and you'll find a source fountain which you can use for unlimited replenishment.