A valid scenario?
Republic has commitments to Delta it can't fulfill & has gone in to bankruptcy (even while making $$$).
Delta has a large fleet of single aisle mainliners that are rapidly coming to the end of their useful life - if not already well past it.
Republic has a large CSeries order it may not be able to use.
Delta can not get the early line positions it needs from either Boeing or Airbus.
Republic offers Delta its early line positions (and at probably lower prices).
Delta takes over Republic's CSeries line positions and conveniently forgives the commitments.
Result: a three way win: Republic gets out from under Delta, Delta gets the jets it needs when it needs them, BA doesn't lose a major order and bags a US Major as a customer to boot.