That works for me! Ko-fi is also better since Etsy tends to punish sellers for untracked letters for whatever reason. If you'd like I can make a custom listing on ko-fi with the stickers you'd want and have the option open for international shipping! Just contact me through there.
I did look into it more and Etsy does not offer tracked international letter mail. So it'd be untracked or the more expensive package international shipping which tends to be around 12+ usd in my experience. I'm gonna go on a whim and say it actually might be easier to do the order through ko-fi.
International Letter mail I'm less experienced with, I have to check the rates and what the usps offers. I'll probably have to go and get some international stamps. If you would like message me on etsy and I can setup any international order through there!
I do occasionally ship to Canada on a case by case basis, but its slow shipping and pretty expensive.