If youre not firstborn youre lastborn.

Paint them in the mighty colors of the executioners since Space Marine 2 and GW show them no love.

War... War never hammers...

I was planning on doing this exact same thing, just ordered some MKII bodies to kitbash with tactical marines for my Minotaurs Badab army, so thanks for the outline on how to go about doing it!

Wild they taken them out. figured it would happen eventually. also wild that there primarus stuff in the list

Scythes of the emperor

I think Star phantoms would be cool. They adore melta and plasma weaponry, and they worship death and see the emperor as a god of death. They have a pretty pure white colour scheme with large accents of black, and skull designs.

Do a fun halved or quartered scheme! I'm currently painting an all-firstborn Marines Errant army, and enjoying it very much. Novamarines, Marines Errant, Howling Griffons, etc... Amazing chapter schemes

Red Scorpions or Crimson Fists have my vote out of the successor chapters! ( Iron Hands would be really cool though :3 )

Fire Angels might be a good pick. I think their red details would be great on your models and they are noted as preferring Heavy Bolters in their tactical squads. They are supposed to be quite new and lacking relics though, so the MK2 legs might not fit in with that idea.
The Blood Ravens are an excellent pick for the classic firstborn look. The MK7 face of a Blood Raven just screams Dawn of War.
I feel like I don't see Storm Wardens that often either. Would be cool to make a Captain or Sergeant with a two-handed Claymore as well.

Plasma gun dude would look epic as a red scorpion vet.

3:55 -- "Cingulum militare" will fit best for this equipment.

0:08 I can only think of the thing that drops out of him meme. 😭

Scythes of the Emperor would be cool to see.

You gotta do the Mentors but with their old symbol from that one drawing of them where its like an alienware baseball

I've always wanted to paint some novamarines, idk It looks like ultramarines but cooler, you could paint your new chapter of novamarines too!

Fire angels would look awesome, also there's the fact that you never see them anywhere.
And that Red arm terminator paint scheme.

Great video, I am currently building a firstborn army for my LGS escalation league. Im doing a Badab War Theme, with each squad been a different loyalist unit.

With how old some of those armour are especially with the legs I think Marines Malevolent would work super well with them

If you want to know those tassels are called pteruges pronounced terugas