I am not sure I see the problem with the meander textures. Are you perhaps referring on the fact that every 5th vertical line is a bit thicker than the others? If so, I am sure that you can avoid that in Ps. Just use the offset effect and you will notice it there also.
As for Icarus, since it isn't a tilled texture, you can't really see any problems. On the other hand, I see now what you mean. You want a way to resize the sprites. The Icarus sprite isn't actually reduced in pixel information. The original pixel dimensions are intact. While the TB image is downscaled either from within C2 or in Ps. The downscale is what causes the artifacts. There isn't anyway around this however, you' ll have to predetermine the actual pixel dimensions for your TB textures. C2 (for the moment) only repeats the original dimensions.