Nice use of those HE Lion parts are shoulder icons, I've considered using them on IG as shoulder pads and as a banner top on some Astral Claws but never as chapter symbols. I like the lasgun mod'd sniper rifle but I don't think the bolter one is quite as clean. Painting wise, I know yellow is a bitch to paint (hence why I stopped at 6 Lamenters before giving up.) but maybe another thin coat of the base yellow over the wash before the highlights would clean it up a bit, they are a bit dirty which is fine but it kind of jars the eye abit as the rest of the minis are so clean. Props on getting the white to be that clean btw.
You're GS'ing is impressive as well, nice work on the cloaks and the helmet mods. Looking forward to seeing where this is going.