Banzai, both you and Casimir are correct in a couple of regards. I've actually been kinda waiting on a response from Hospitallers on this so I'm glad you chimed in.
The scripts.txt actually does color the back of the black&white Hospitaller heraldics as the same white to match the cross. I can very easily go back and try to make the backs black again, however there are several problems with this.
When I did it before, the almost 'velvet' appearance of the front threw the colors off and there's no way to actually match that on the back. I tried several shades of black, off-black, grey - all sampled from from the front mesh of shades. None of them worked and tbh, looked rather shitty.
There's really only one way to fix this, and that's for you to allow me to re-shade the front to where it reduces or totally gets rid of the 'shine' effect that can't be reproduced on the back.
Or, the other option is that I can match it as close as I can and we can just roll with it.
Now as far as the fuzziness... unfortunately there's nothing that can be done for that. It's a Warband issue with the Heraldic with Surcoat. What happens is that the graphic gets spread over a larger area, depixelating the image. With the other Heraldics though it's not an issue since the 'canvas' is almost half the size. The images come out a lot sharper.
Lastly, like Casimir mentioned, to change the emblem positioning on the Heraldics, you have to download and install the file he listed in his post. That will put the emblems on the chest of heraldics.
Otherwise, in order for Clan's emblem to show up correctly in the circle above their head, it has to be in a certain position in the banner.dds. Unfortunately that defaults the emblem to be right along the belt line of heraldics, unless a mod like the one above is installed to correct it.