Looking for critique for my Mage: the Awakening game.

Hello Myth-Weavers!

I'll cut straight to the chase, I am gearing up to run a chronicle of Mage the Awakening next week and need some help turning a rough idea into a 'somewhat' laid out adventure for my players.

Here is a synopsis of what the game will cover:

The blue-collar town of Blackrock Michigan has experienced a magical catastrophe. Now the city is in a magical limbo as the barriers between worlds begin to break down. Cut off from the rest of the world, the PCs must try to figure out what has happened to sunder their town from the Fallen World.

A more detailed explanation would be that after centuries of confinement an Abyssal being is released from its prison and its influence is a corruption at the very heart of reality. The corruption eats away at the barriers that separate the Fallen World from other places, such as the Shadow. As the supernatural degeneration accelerates the city of Blackrock will start to loose its grounding in the Fallen World. As the Great Maw, the imprisoned Abyssal being, becomes freed the corrosion will reach cataclysmic levels as Blackrock is thrown fully from the material world.

In the aftermath of Great Maw's freedom it claims dominion over Blackrock and sets three of its followers as stewards over parts of the Blackrock.

The PCs as newly awakened mages will have to survive and make allies quickly in this new and terrifying world. They will ultimately work towards reversing the hold Great Maw has on the town of Blackrock and return it to the Material World.

The potential allies the PCs can work with would be the following:
  • The Blackrock Police Department: Full of sleepers, but sleepers with resources to defend themselves with.
    The Hidden Path: A cabal of Mysterium Mages sent by the Eastern Consilium in Boston.
    The Silver Snake: A cabal of Mages outside of Awakened society. They exist as the remnants of the American tribe that originally bound Great Maw and are devouted to stopping it.
    The Dark Angels: A pack of werewolves investigating corruption in the spirit world when they became stranded in Blackrock.
    The Blackrock Militia: A rag tag band of townsfolk who are attempting to defend themselves.
    The Court of Dawn: A spirit court lead by First Fire, a powerful spirit of flames.

The PCs interactions with the various factions here would grant the PCs various advantages in their journey to help save Blackrock. For example, the Dark Angels are experts on spirits, and can offer the PCs excellent advice on how to deal with dealing with rogue spirits. The Silver Snake on the other hand have been dealing with Great Maw for their entire history and know more about it than anything else.

However, these groups are not willing to help the PCs for free. The more resources they give the PCs, the more they will expect in return. Times are tough in Blackrock, and survival means cooperation. So any aid the PCs receive will come at the cost of assisting the faction in question.

The central antagonist to this chronicle would be the Abyssal being Great Maw, a powerful denizen of the Abyss who seeks to consume everything to fill the void inside him. Great Maw was originally bound by the Native American tribe that the Silver Snake cabal descends from, however it has since broken free due to loggers. Among its followers, it has appointed three to rule over different areas of Blackrock while Great Maw sees how to return to the Abyss.

The Three Chosen are:

Nozradoom: A corrupted spirit of Joy and Light
Kurz: An Abyssal being of violence and domination
Nar'sil: An Abyssal being of sorrow and grief.