Mono Black Rogues (Modern) (Modern)

This is very much a work in progress as I'm completely new to modern.

The idea is to threaten auto wins versus certain decks due to Dauthi Voidwalker + Thoughtseize / Inquisition of Kozilek / Thieves' Guild Enforcer
On that note, does Dauthi Voidwalker render Thieves' Guild Enforcer too useless? Or is Voidwalker a must-answer threat that if so re-enables Enforcer?

Most of our creatures are very evasive which goes well with Stinkdrinker Bandit, can be prowled out after a T1 rogue or dropped on T4 for a big swing

Unsure if Oona's Blackguard is too slow? I imagine T1 Thoughseize/Kozilek T2 Oona T3 two rogues is fine?

I'm trying out Sygg, River Cutthroat, the dream would be to use him in conjunction with Shrieking Affliction but that seems like christmas land to me or an entirely different deck

Is 3 Fatal Push too few, too many? Do I not run them game 1 or hedge my bets?

Bitterblossom can be very grindy and does well with Oona's Blackguard, Metallic Mimic and Stinkdrinker but maybe the deck wants to be faster than a summoning sick 1/1 every upkeep?

I considered snow-lands for Faceless Haven but this deck needs to play something turn 1 every game and faceless haven inhibits that, there's also a few BB spells that makes it bad T2, instead I run Cavern of Souls and Howltooth Hollow (low opportunity cost). with no 3-drop in the mainboard Agadeem's Awakening doesn't seem worth it. This also enables Break the Ice's overload but that doesn't strike me as very relevant
Pay attention to the fact that you can't cast Thoughtseize / Kozilek with mana from Cavern of Souls, maybe I should run fewer than 4 of Cavern & Howltooth, considering Castle Locthwain

The sideboard is something I'm very unsure about due to my inexperience with the Modern meta, I'd like to include some archetype hosers, life gain for the burn matchup and whatever else might be useful, preferably while still staying rogues.

You could try the deck with Lurrus as a companion by excluding the Stinkdrinkers but I think you'd be better off not mono-black in that case.

Thanks for your patience with my rambling! If you're experienced with modern or have any suggestions, feel free to comment.