As a founding member and the first judge of Barca I might be able to shine some insight into Barca's stance on religion, including SA. When I was appointed Judge I wrote out the laws of our republic and presented them to the Senate. The Senat approved the laws I wrote in their entirety.
As far as religion goes, Barca's laws do not specify anything regarding personal practice thus only the laws of the Barca-Terran-D'Hara federation apply for the time being. Preaching or building temples is prohibited for ALL religions unless a representative of a religion gains permission from the Senate. Thus far only Verdis Elementism and I believe Truinism have sought and gained that approval.
As far as enforcement goes it is likely that the judge would order that preaching stop pending approval of the Senate. If a Senator built a temple without permission, I imagine that the Senator would be fined then Senate would decide if they are willing to accept Temples of that faith in Barca. If not, the offending Senator will be ordered to get rid of the temple. If they do not they will be banned and the new Senator will be tasked with getting rid of the temple. No land owning Senator is exempt from banning as a Lord/Duke can not simultaneously hold a council position.
Barca has the laws and tools, in theory, to control the spread of religions. Of course I can only say what my character would have done. Cedric is hard nosed when it comes to seeing laws followed. None of this would happen unless the senate and judge follow through and I can not say if they would.
As far as Julius' power goes, it officially does not go very far. If one reads our laws it can be clearly seen that he is subject to the Senate will and not the other way around. Thus far, however, the Senate has been content to let him push things through. Most nobles of Barca still give him credit for organizing the founding of Barca and for securing the support of Terran and D'Hara. I doubt that any future leader of Barca will enjoy the same level of autonomy that Julius does.
As far as Barca's general feelings toward SA... I would consider "cautious" the best word. From my perspective in Barca SA has been a force that either incorporates or destroys. None of this makes Barca feel warm and fuzzy when thinking of how the religion might affect things if it were allowed free reign in our little republic!
