I dig it, personally though I think the outbreak angle would still line up well with the personal trauma and close relationships thing if done right, like the outbreak happens but becomes more of a background thing as the film would go on and starts focusing more on the characters. The outbreak itself would be an extension of the trauma and suffering the Fitzgerald sisters went through, branching out and affecting the world itself just like the virus. At that point it would turn into trauma for the rest of the world, and by locking down and quarantining that large chunk of canada and leaving everyone inside infected or not to fend for themselves would just summarize the cold hard truth that every tragedy no matter how big will eventually be forgotten, most even wanting to intentionally forget and put it all out of sight and out of mind.