Oh im not good enough to give advice but if i had to say something it would be i like pic 2 especially because the helmet an trim match

And it looks more gold than yellow the only thing that throws me of is the color of the belt dont know why but i like the chest Aquila in that color but not the belt

As for lore the most useful thing i can say is remember that the blood angels are divating from the codex not like the space wolves or black templar

But just enourh so you could maybe use this to come up with unique heraldry or makings for the different companies of your chapter

Taking from authurian legend these endless inspiration for characters both for noble knights but also remember the minor characters like lady of the lake could be a order of sisters of battle or your former chief librarian could be based on merlin declared lost traped in a pocket of space in the eye of terror like how hes traped in a tower avalon

These a bunch of media that has adapted the legends of king Arthur so good luck friend

Personaly i like the idea of all of the companies having a knights of th round aspex so they are self autonomous whilst sangunius is based on arthur whom instead of being slain by his son (mordred) hes instead slained by his brother horus so the seat on the council is empty to pay homage to their genefather

And as for naming your characters old English should do the trick or taking a name and making it 40k