Death Company Terminators do not exist, so I doubt they will be picked up unless you price them very low. As for their armament, if you give them ALL TH/SS then you lose out on their +1 Initiative in the Baal host. I would make four of the ten with Lightning Claws, since it is very common to put atleast two per five with LCs and seriously consider one with a banner. If you sell them together, have a Lightning Claw and a TH/SS model with the extra love and care to be able to be represented as a Sergeant, a single banner, a mix of weapons in the usual Blood Angel colors and I bet that would sell no problem. Orbital Intervention Force has done a good job on making Blood Angel players want some Terminators. The Cataphractii I'd sell on their own with a regular build. Combi Bolters, Power Fists, a Typhoon Missile Launcher. Again, in Orbital, they can fire twice if they are run as normal Terminators and if they're run as 30k variants, or even as 40k Cataphractii, they can't Sweeping Advance. So there's no point in them being a bully unit of AP3 if they can't chase after combat.
Death Company are very simple. Everyone gets Jump Packs and one in five gets a Powerfist, the rest get nothing. That is the only popular way to run them and straying from that might make it more challenging to sell the models. Tycho is not a popular choice at all so I would dedicate the current 15 to Jump Packs and then get an additional five for Tycho as your pet project. This lets you sell the lot as a pair of Formations plus extra models, which is a great place for new players to start or experienced players to kick off their own stuff further.
Paint is simple. Stick to the codex for it. For Blood Angel red: Mephiston Red, Agrax or Carroburg wash, Evil Sunz Scarlet highlight, Fire Dragon Bright fine highlight if you're talented. Green contrasts beautifully for lenses. Black is black and folks have different ways of making black pop. For instance, I use a Chaos Black primer, a mix of Eshin Grey and Abbadon Black as the base and then hit it liberally with Nuln Oil to naturally shade the recesses in what I feel is a more shadowy look than the edge highlighting or weathering I've seen other folks do. I am by no means a professional painter though and that's just what looks good to me. Stick to the traditional gold on the Sanguinor. He's not a normal type of character and could be compared to an angel descending when the host is struggling in war. He doesn't get dressed in the morning like other Marines, so keep him in those normal colors and he's more likely to be used.
So to sell this, with the extra five DC guys on foot and 15 in the air, you have the Death Company Strike Force with a Chaplain, the ability to split the 15 into a squad of eight and a squad of seven, and with three Powerfists to give between them all. You should get some considerable interest from that group. Then you also have an Archangels Orbital Intervention Force with the Terminators. Sadly all of the Special Characters don't fit into either of those but it's not that big of a deal. Many people will just consider them extra options. And if they look good, all the better. That's atleast the sort of setup that I'd buy if I were purchasing.