Hi,
My honest opinion is that you do not need a bass or keyboards on this piece, as it seems to me that you both did things really nice and well enough to stand up on its own. You might need to use a few musicians, if you have to perform this somewhere, I would guess, but ... for my tastes, at this moment, I would rather have the feeling that it has right now, and not spread it out with more folks that might not understand or catch up with where you both are at.
If I have one comment, and this is just me, and please do not take it with so much salt and pepper that you gag and throw up ... but I would like to recommend a few bits and pieces here on the drumming cleaned up so that he is not just "keeping time" and using the same snare and hi-hat non stop. I might even recommend listening to the John Bonham drumming breakdown, so there is an example of some different things that can be done with drumming, that are not just keeping track of the time, which you can do with a mechanical something or other, and this would allow the drummer to do more than just keeping time for you ... I think, it would be best to allow you both total freedom. Another fun example, but probably harder to break down, is listening to Tangerine Dream in their last few albums (just get Supernormal) and see how the lady adds syncopated drums to her own beat ... and while I would love to see more variety from her, what is with her in the background is superb.
One example of drummer and keyboards (not guitar in this example) catch on to "Seventh Wave" and their sublime two albums so that you can get the idea that more musicians are not always necessary to create something original.
I like this piece of music, and am on the second listen already!