As for "entrance applause", well... On a related note...
When I saw Company last Saturday, no one applauded after Barbara Walsh finished singing "The Ladies Who Lunch", but it was designed that way. While talking with Barbara after the show, we discussed some of the different "options" they had explored during rehearsals, and how the final variation was her idea. -It's amazing how holding a certain pose, or changing where to break a line can affect some much more than the timing of a scene. In any case, she did say that on those rare nights when she did get applause after the number, that the feeling of the following scene changed greatly - for the audience. More laughs. -Otherwise, the next applause "break" would not come until after "Being Alive". And, man, did I applaud for that!