Another mixing question

so the aim is to get the main output peaking between -6 and -9 for a version that's ready for mastering, and as I understanding it without any limiting on the main channel. But

can you use compression and eq on the main master out?

And does it matter what level the bus faders are in relation to the samples volumes? Like does it matter if you have quiet samples and loud faders, or loud samples and quieter faders?

It's always helpful to read your guys thoughts