#1
Ok, so I'm getting a bit more into the more advanced soloing, and I need help with applying the modes. Example, if I'm soloing over an Em chord in... well, whatever key it would fit, could I just use a Dorian or Phrygian or whatever minor scale over the Em chord regardless of what key the Em chords in, or is there some rules to that?
"Isn't it amazing anything's accomplished
When the little sensation gets in your way
Not one ambition whisperin' over your shoulder
Isn't it amazing you can do anything " - Gord Downie

From the song " Fireworks"
#2
If it's just an E minor chord, you have a ton of options. Anything with an E, G, and B is acceptable, so many scales, including the ones you named, are fine.

When you get into progressions is when you start to put limitations on what you can play, but not really. What if you have an Em--->D progression. The notes used are E G B D F# A. The obvious scales to use are Aeolian and Dorian. But, you could approach each chord independently. You could use E Phrygian over the Em chord and D Phrygian Dominant over the D chord. This is more of a jazz thing, but it can be cool.
#3
Thanks. That was what I was thinking, I just wasn't quite sure.
"Isn't it amazing anything's accomplished
When the little sensation gets in your way
Not one ambition whisperin' over your shoulder
Isn't it amazing you can do anything " - Gord Downie

From the song " Fireworks"