haha, yeah, although I’m rarely using it to boost, just to limit/tame peaks
I usually use the chain verb (reverb with the wet signal ducked by the dry - so that transients and body are dry and tails are wet) for cohesion in the percussion section (not kick and bass, however), sending my snares, claps, hihats, cymbals, and sometimes auxiliary percs to it to create a sense of space. usually fairly subtle, except maybe on the snare/clap. Convolvers are awesome, magical creatures that multiply audio signals - usually people use them for reverbs and delays, but there are all kinds of interesting, exotic effects that you can use them for, depending on the impulse loaded. It can be really fun to make your own impulses using unusual material to create dramatic ambiences and transformations of the original material.
I have a “compressor” on every instrument track, and mostly just use the bus compressor on groups. It’s nice to have the ability to soften the knee for more transparent compression on busses, and I don’t rely on the bus compressor to tame peaks… maximizers for me, lol
because basses are awesome 
I definitely don’t always use all four, in fact most tracks have just one or two, but I generally like to keep each instrument on a separate track and dial in individual eq and compression, etc. since bass is such an important part of most of the music I make, I like to have as much control here as i can, hence, lots of bass tracks
the left channel info is in the difference between the two channels, along with the right. think “mono” or “mid” is what’s identical between the two channels, while “sides” is what’s different. subtract the identical (by inverting one of the channels) and you’re left with the difference
check this out, it kind of does that: Dynamic Eq as a replace for Multiband Compressor - #3 by slujr