When I try playing trills between my first and third fingers, the second and fourth finger make the same movement as the third finger. Is it normal to have those other two fingers moving or is my finger independence lacking?
my fingers do that too if i move my finger far off of the fret, but for fast trills they don't really move. it doesn't really matter
as long as those other fingers dont hit the fret board it should be fine
That's just a tendon-related thing. Don't worry about it.