Some nice cards might include Cartel Aristocrat, Lightning Helix, Terminate, Olivia Voldaren. I'd also try and get a couple Blood Crypt unless you already have the mana the way you like.

Bloodsoaked Champion would fit in here quite nicely. Also if you put in Bone Splinters ot lets you sac one of your creatures and kills a creature all in 1, and Tragic Slip is a good kill spell in this deck. Also Mentor of the Meek to help with some draw power also Skirsdag High Priest as a game ender.

Scratch Olivia Voldaren, I meant to suggest Falkenrath Aristocrat.

What I'm really having trouble on is getting the hand I need at the start. Like maybe I'll start with AEther Vial Champion of the Parish and Xathrid Necromancer but I wont draw into a reliable way to sacrifice creatures, or not draw any creatures to sacrifice.

Basically I feel like the deck is bloated with things that dont fit with the combo, so really I would like suggestions on what to remove from the deck so to better sharped the Xathrid Necromancer + Champion of the Parish + Thatcher Revolt combo.

@tclaw12 @Havok Bane thanks for those suggestions, Ill be sure to playtest them all

If you want to go the full Falkenrath Aristocrat/Cartel Aristocrat/Skirsdag High Priest route that the other comments are suggesting, there are some other changes that you should probably make to accommodate this shift in game-plan. These three creatures, forming much of the core of the Aristocrats build from Innistrad, work best when you are A.) sacrificing human tokens instead of actual creatures, and B.) when you can choose exactly how and when each token dies. For an Aristocrats build, you might want to run Gather the Townsfolk over Thatcher Revolt to both lower the curve and to ensure that your human tokens will stay on the field until you need them. With Falkenrath Aristocrat, you will often get more mileage out of sacrificing two humans over two turns than sacrificing three tokens on one turn. This allows you to keep your Aristocrats indestructible or protected for as long as possible while devoting the fewest possible resources to doing so. Additionally, it may be better to remove less effective sac-outlets that, while more useful for generating Xathrid Necromancer tokens, take away sacrifices from your Aristocrats. These would include Death Cultist and Viscera Seer. Furthermore, due to the self-protecting nature of the Aristocrats, you will not have nearly as much need for cards like Emerge Unscathed. The Aristocrats will be able to pick up the slack once swinging with Champion of the Parish is no longer effective. Again, this only really applies if you intend to go the Aristocrats path with your deck. I'm not trying to push you there, only give you advice for if you choose to build on those lines. Whether or not you choose to run the Aristocrats build, I would advise you to shy away from AEther Vial for this deck. AEther Vial is really not useful at all here. AEther Vial in modern is basically only at max effectiveness when your deck either has a lot of two drop creatures that need to be spammed at once (example: Merfolk tribal) or you need to cheat creatures into play as a way to circumvent counterspells or casting restrictions (examples: Serra Avenger, Myr Superion). You really don't need a Vial in this deck, especially if you intend to set it to three, where it could only tap for 4/56 of your cards.

I think I would agree with some of the comments above.. AEther Vial is a pretty sweet card, but I don't think you need it here.. -4 of those.. Even if you really want to play the vial, I think 4 is too many for this deck.

You mentioned some constistancy issues with token generators and sacrifice engines, so here are my recommendations for each:

Gather the Townsfolk in addition to the Thatcher Revolts you're already running.

Thraben Doomsayer needs to be in this deck. He combos really well with your theme and Champion of the Parish or Falkenrath Aristocrat if you decide to run her.

Stronghold Assassin or Skirsdag Flayer can help you with spot removal and puts some of your instant spells on a body

Corpse Traders, Nezumi Bone-Reader, and Mind Slash do the exact same thing as Inquisition of Kozilek and gives you recursion for the ability or more creatures to sacrifice.

Falkenrath Torturer can be just as effective as Falkenrath Aristocrat or Champion of the Parish.

Archdemon of Unx, Ghoulcaller Gisa and Xathrid Demon are also great sac engines and late game finishers

All those recommendations will up your mana curve quite a bit, so if you decide not to use any of them.. I totally get it BUT you have to run Dictate of Erebos in a sac deck.. I really cant see a reason not to clear the board while stacking yours - it combos really well with Grave Betrayal too. Endless Ranks of the Dead would combo really well in this deck with a Coat of Arms too if you want things to get ridiculously out of control.

@ppledger Thanks for your advice. I think going the route of Aristocrat would be most beneficial because what I have now is clunky at best. The protection aspect of Cartel Aristocrat really frees up a lot of space. However, I really want to keep the Xathrid Necromancer+Champion of the Parish+Thatcher Revolt combo since its the reason I built the deck in the first place do you think they are mutually exclusive? I'm surprised at how I miss used AEther Vial thanks for the clarification.I'll update the decklist with the suggestions and playtest it. Could use help determining how much of each spell I should have.

why you no Athreos, God of Passage?

Thankfully, that combo is in no way mutually exclusive to an Aristocrats build. Thatcher Revolt was more of a Hellrider card than an Aristocrats card, but I see no reason why you can't run it just 'cause. :D

Oh, and take out Ghoulcaller Gisa and Stronghold Assassin. They aren't modern legal.

I'm not sure about Cavern in your Vampire Human Advisor Soldier Cleric Wizard tribal deck.

One card I would highly recommend is Bloodsoaked Champion. You can sac him over and over and he keeps coming back for more. He's a human too so he triggers the necromancer.