IMO I’d try to avoid applying reverb to the percussion if you have the option.
IMO dynamic range compression should be applied to the final mix just before you convert to MP3, but you may also apply it to individual channels, (BTW there is dynamic range compression plugin by Steve).
Your tracks are stereo 44100Hz mp3 which have a bit rate of 128Kbps which is too low : this means all the frequencies above 16KHz have been chopped off, ( have a look at “plot spectrum” in Analyze). You should use a bit rate of 256, or 320 Kbps if you are aiming for CD quality.