If a company goes bust and is bought over, lets say the new company wants to take over the existing contracts. Fine as long as you adhere to the existing conditions in the contract which by the way includes a big penalty for the late delivery of goods. Oh no thanks say the newco we dont want that. Alright then come and negotiate a completly new contract, by the way we wont be going easy on you on he deal and might give the contract to someone else. eh hange on might be better just to take the penalties.
Regarding your second point, they cant! Newco have no titles