Oh yeah, as far as silence, it can mean that it just needs invitation to express the negative, or it can be their way of trying to recalibrate when there is hurt. It can also mean that they are in a bad state emotionally. A Fe user that's doing okay will usually be kind of noisier than most Fi-ers about what is going on, but it's actually a good sign. A Fe user that's not doing so good will tend to talk less. That's when you should worry about them and start asking questions to find out where the problem lies.
The Fe user I know, this is completely true about the talking and the silence. Your thoughts on this have confirmed what I've observed. Being Fi, I'm usually only concerned with what I'm feeling in respect to how my friends are feeling. I've learned that with Fe, there is more of an expectation that the feeling should be on the surface. If it's not, it makes them uncomfortable and therefore, silent. But my silence doesn't mean rejection. In these situations, I've forced myself to talk as someone with Fe needs that. I do too, but I don't mind long silences.