Most compressors have 2 variables, compression, which is how much to compress the signals, and release, which is how long to hold the compression for, the release can be used to increase the sustain of the notes. Compression is normally used on vocals, bass, and drums, as well as other instruments as needed. It can be used while recording, or in the final mix down. Reverb is an effect that changes the original sound from sounding like it was recorded in a closet, into sounding like it was recorded in a gymnasium. It adds depth and ambiance to your music.
Most people like to add at least some reverb to the whole mix, to make it sound more full.
As long as your -10 equipment can handle the higher input level you'll be fine. Prevent overloading it by keeping its input-level set low. Balanced lines offer excellent immunity from hum and noise pickup. Any noise pick up cancels out neatly. These are line levels.