I do think it looks good and could be left as is.
Another color to maybe consider would be grey with either the white or black. I would do it with the white.
I know you stated what other Kona fabric but maybe a black/grey or white with a print of either grey/black or white would look good too. Solids can tend to make things look a bit too crisp/stark to me but that is a personal preference.
Great fabrics and a fun quilt pattern!