As long as the tickets are bought as a single journey, then you are safe as the airline will re-book you on the next available flight.
Don't worry
Yes they wiil, but as I said, they will almost certainly not pay for your accommodation and other out of pocket expenses
if you miss the inbound flight from PHL to MAN.
In that case would the fare be cheaper than going via London, Amsterdam etc?
Try skyscanner.net for a variety of options and fares
