Finally listened. Kind of subdued. I would have made it shorter perhaps in length (start with the guitar where it starts) but who am I to say. I get going to and the song turns out longer than I thought it would be.
But trying to make it sound real probably is not going to be done without real musicians playing each instrument.
I do not worry about that, and just do the song (although I try to make it sound like a more real musician playing it).
That probably won't happen so just getting the song down and getting it done is what can be expected.
In this day and age of music, I really think that people will accept any song that is fine to listen to, and I would not worry about the rest. Of course you can try and perhaps driving yourself crazy.
The mix sounded fine to me but then that is usually what I say anyway. So no nitpicking from me, except it may sound better fuller. Perhaps you can do that, perhaps not - any which way you may think of - perhaps doubling the tracks on certain instruments and changing pitch slightly to add more fullness to the sound.
That's music, and perhaps a lot of it is just going to be editing in that kind of sense of making it into what you want it to be.