For EQ, it depends on what it sounds like(how well was it recorded?), what I want it to sound like(Mormon Tabernacle or Bohemian Rhapsody?), and what the voices are competing with(other instruments?). My only rules are:
1-I usually dip a little around 350-400(but this is to leave space for a lead vocal which you may not have)
2-I hi-pass to keep the low end clean
3-dip any buildup frequencies(if any exist)
As for pan, there are no rules(even my EQ rule is not a rule
). You might want all male voices on one side and female on the other. You might want everything kept tight. You might want to experiment(highly recommended). For me, I tend to pan things so every part has its duplicate panned the other way. This is a great excuse to try everything and fine out what works best for your particular project
