No. Each Catholic should form his conscience and, where there is a question, talk to an ordained person. We run into problems, though, when these ordained persons have an agenda separate from Church teaching... and there is no monopoly of this situation in the Catholic Church.
Simply go by authoritative declarations made prior to 1960 and only those subsequent ones which re-affirm and clarify.
No. That’s not what the means.
It means that, if a Pope contradicts what the Church has alway taught, then he is teaching error.
There’s no “personal interpretation” involved. Either the current Pope is teaching what the Church has always taught, or he is contradicting what the Church has always taught.
(I am not speaking here of matters like global warming, on which Bergoglio just teaches lies, and the Church has no teaching. I’m talking about the teaching of Jesus wherein he defined that marriage is indissoluble.)