On that 4″ lead you have a wiped joint before the cast iron hub. You can melt that solder off the brass ferrel that it i attached to and cut lead out inside the brass ferrel and use a nohub band on the ferrel that goes to pvc and cut a piece of 4″ pvc and band themtogether.
Are you can nelt the lead joint out of the hub and install a 8″ piece of 4 ” cast iron and use a band from ci. to pvc. Pour the castirn joint. and caulk it. Are call a Lic. plumber.