As far as coming up to the galley. If the curtain is closed it is closed for a reason.
Flight attendants have to eat too and are trying to do it out of view of the customers.
It's been a long time since I've seen a front curtain closed. On the most
recent occasion, I inquired, and the word from the FAs was that it was
closed to prevent the F pax from having to see into the kitchen ... but if
they wanted to, that was okay, and it was certainly fine to breach the
barrier to find the toilet.