It looks fine to me, the colors look strange possibly because the skylights intensity was fairly high. You only messed up the output for the debug colors (you had the switch on your RHAO output and it should have been on your albedo), then I changed the normal map to use the normal map sampling mode. You aren’t using a channel packed one, so you can just use Unreals standard that means the offsets around the rotation aren’t needed and the function at the end which reconstructs the blue channel isn’t needed either.
I’ve made a pull request to your GitHub project, it should merge without any issues.
Weight map works such that it multiplies the masks from the tiles with the height values from your textures and then calculates a weight for each of the 3 texture samples such that the total adds up to 1. With this weight, you can now multiply the 3 texture samples and add them together to get your final values.
In the next revision of this I’ll make sure to include a version with a seperate normal map, but for anyone looking to use it with a standard normal map your version with my fixes should be a good starting point now.