Since you can't retrack you can cheat a little - clone the guitar track but add a tiny, tiny bit of delay & make it 100% wet - no dry from the delay process. That'll give you a guitar that''s ALMOST the same as the L - you'll need to experiment with the delay lebgth to make it work. Cna be done, isn't the best option but you've said you can't add another gtr.
The bass is OK but needs a littl definition - IF you get it stem mastered the ME will prpbably do that for you BUT if you're going for a stereo track to be mastered you should put a little 3 db peak at 3khz with a varrow Q.
Once there are two gts panned L & R you could create a stereo spread of the bongo/s.
When the drums break comes in you ought to have more snap - v/often thet break is on timbale or something else that cuts through with a big snap sound. Not for all the snare just the breaks.
NO MORE reverb, please unless you're going for a more dub reading.
Less reverb would be better to my ears -
ESP on the guitar (again with 2 you'd not need the reverb).
Good song & a good mix given the restrictions.
I've just been through a slow process of having 13 tracks mastered, (slow because I could only afford to get one done at a time). If you break you song down into sub mixes: bass gtr, snare, rest of drums, guitars, vox & so forth do an export of each of those individually then recombine them in a new project you'll get a better idea of how things fit & what needs to be done to each group in the same way as a stem mix would work for you.
have a listen to my last couple of posted tracks to hear what stem mixing can do for an amateur.
