Vampire Coast early is, imo:
A gun line. Usually handgunners/hand cannons. A few deck gunners.
Some meat. Usually polearm deckhands, but any melee that can hold for a bit works. Not too many, you’re mostly about the gun line.
A mortar. Maybe 2. Early on mortars are huge.
Then it’s just a matter of repositioning to shoot things the meatshields are tanking from the flanks. Handgunners are also meat shields at the end of the day. Everything is a meat shield early other than mortars, but ideally you want the good meat doing the blocking while everyone shoots things.
Don’t discount Vampires or Mornguls heroes either, they can generally hold their own. Wights are a force multiplier, they buff ranged and basically everything is ranged. Also they can reload artillery. A lot. Their damage is actually good as well.
Also make sure you get Lore of Vampires ASAP. Being able to drop Invocation of Nehek and trigger Curse of Undeath is as important to Coast as it is Counts, and it’s harder for you to get access to it since you don’t have a bunch of Necromancers farting around to do it for you. Getting Wind of Death is never a bad thing either. It’s basically why Counts are playable.
Later on most people replace their meat with Rotting Prometheans (ideally gunnery mobs) since they can hold well, are fast enough to intercept things and are low, big model counts which means your gun line can still shoot whatever they’re fighting pretty well.
Very early on Bloated Corpses can kill entire units easily, just make sure they aren’t near you when they die. Hide them and then have them run at a unit once it’s too close to react.
Basically the most of the army early is replacable with Raise Dead. If you lose handgunners, odds are you can just summon new ones at full health. If not Gunnery Mobs work. Deckhands if it’s dire, though those get phased out quick.
Mostly you want to give your artillery time to rack up kills. Mortars and later Queen Bess can wipe out a ton of stuff.
When it comes to the melee game, it’s a lot harder. Most units are hammers, not anvils at the end of the day. Depth Guard are better than they used to be, but they’re still mostly garbage and need to be with a swarm of zombies to have much hope of making it through a fight with their terrible unit count. Polearm Depth Guard to deal with rogue dinos is really the only ones I consider at this point and honestly by then you can have Necrofex’s which can just shoot said dinos in the face. They can also shoot flying crap, which the Depth Guard mostly watch kill everything.
Eventually most fights you’ll kill everything before it can get into melee with you unless it’s like a dragon or phoenix, but it takes a while getting there. Fortunately disposable troops are a thing you’ve got in spades and most of them carry guns, which is better than skeleton warriors or zombies by quite a bit.