Between tracking and mixing...

Hey everyone, I'm very passionate about recording but what I know is only from experience. I have some technical gaps in my verbiage and knowledge. I'm fortunate to have finally collected everything I need for recording a live band. I'm using a MOTU 8pre and 896mk3 together as an interface. My mic knowledge is very limited a definition of the different types and best uses would be sweet.

For HiHat

For two overheads

For snare and 3 toms

For the bass drum

Drum tuning tips would be sweet!

to mic the cabinet

Run direct

3x misc. mics for live vocals = Running these through the MOTU I get much more feedback at lower levels then if I run these mics direct into the PA. ???

Reason from a laptop is also run through the MOTU 896.

My question is...
I'm recording live in a less then perfect environment, passing trains and all. Is there any standard treatment of the raw audio captured between the tracking and mixing process? An acquaintance was telling me they like to take the wave image make it huge and remove a certain level of quieter material from the source.

Short of recording things more independently anything I'm missing or might benefit from adopting? I'm currently working on ear training for EQ and compression, I typically will compress the bass, bass drum, and again compress the whole mix before the final limit to bring it up to level.

Thanks in advance!