Congrats! I love the rust color!
I don't know how much you want to spend on him, or how much you have, but I had a little fun in the demo and made some options
https://imgur.com/a/miUH0Id
I mostly focused on bringing out the rust and limiting the reed. (I kinda like clashing accents but I think I'm in the minority :P) I made some pebble-only changes and also some moonstone variations, but I didn't mess with the pose.
Overall I'd suggest:
Accent: Cozen or maned, assuming you want to minimize the color, otherwise stripes, merle, or leave it as brush.
Under: Honestly anything looks cute IMO. Stripes and maned give you more of the top color, but leaving it as cozen or changing it to brush is gorgeous anyway.
Top: Timber and merle both bring make the rust more prominent, or stripes can add a nice gradient.
This is my personal favorite:
cozen accent, brush under, and stripes top. I feel like his eyes pop more with the shadow base behind it, and the dark of his paws and back of his ears give him a mysterious look.
Of course this could be entirely what you're not looking for lmao