#2
Yes, in general inner voices are typically very static in traditional part writing.



Ignore the numbers and shit, but see how the first two chords are Eb to Cmin and the tenor sustains that Eb and then on beat 4 to beat 1 it goes from Cmin to Fmin and the alto sustains that C across both beats. This is a pretty terrible example of good part writing, but the principle that you're talking about is present.

Basic rule of thumb though, the inner voices should move as little as possible. It's not uncommon to see a single note held for measures on end in the alto/tenor if the harmony supports it. The idea is that if there is a common tone between two chords you can have the inner voices stay on that common tone. It's not necessarily something to shoot for, but if it's there do it.