If I put textures in an atlas that are supposed to tile, is there anyway to make them tile? Short of cutting up my object into squares and mapping them all over the same spot in the UV.
Nope. Your instincts are correct. If the texture is atlased, you have to do tiling using mesh geometry. Which, by the way, is how that is done in most cases. In theory you could make a custom shader that wrapped the UVs at different spots… but… yeah.
You can fold them over themselves, instead, if you’re okay with the resultant mirroring effect. That takes fewer vertices.