Couple of things here.  First, you can call it what ever you want but if you are drafting language that causes people who have a Constitutional duty to uphold the Constitution and it's laws to not enforce those laws, you are in fact breaking the law and can be held liable for it.  It's not what you are calling it, sanctuary city or what ever, it's what you are doing to illegally flaunt Constitutional law and you can be jailed for that. 
Next, in another article it appears an illegal quorum was established when three counsel members attended the meeting to discuss sanctuary status that was being address by counsel and attempts to pass an ordinance.  This topic at the church was known, well advertised and the counsel members should have known that when there was a quorum established that one of them should have left the meeting in order to comply with the law.  
Ignorance of those laws, especially by a seated Counsel member, is not an excuse and they could be fined removed from office.