Hi, are these compatible with the Old School modern set?
Not exactly. These are made to be better than the original Old School modern, as an expanded remaster. The color palette is different and the characters are in a new style. Most of the material from the original Old School modern set is here, recreated in the new Omega style.
But they do use the same base tile size, so they can work together without any problems. It just might require a little bit of editing in order for the visuals to match, mostly by color scheme.
I hope that makes sense. Thanks!