great stuff ! magnificant guitars and a nice spirit/feel to it.
Sounds very clear, well balanced, open.
if you fixed this in a day, take my hat off
what might help the mix (not sure) is if you take 1 or 2 instruments that play throughout the song...and put them mono in center only with no side signal (or maybe just a tiny bit) (flip mono interleave button on track, or take down side signal with Channel Tools fe).
I'm thinking that might give you a better image, more solid, and better seperation between the instruments.
That's just something I'd try & not sure if it really works.
In terms of arrangement, maybe from a loop or so, you could build a sort of a very catchy theme (easy Keltic melody line on guitar + flutes fe) and let that come back a few times...and do some other stuff in between.
enjoyed listening to the song + all the best.