Heat. If you have a torch, heat the female end until it's orange. Then use a pipewrench. If you don't have a torch, sometimes putting a a pipe over the handle of a pipewrench can give you a lot more leverage and strength. Good luck.
Cast iron is not threaded, steel pipe is.
A flange threaded in center used for weld or different types of threaded pipe.
threaded pipe use an extractor
purchase a threaded connector, for the PVC pipe, then purchase a metal threaded adaptor for soft pipe, see your hardware man,
2" from finished wall to end of 1" threaded pipe.
Black steel depending on schedule can be threaded from 1/8" - 8" Personally I threaded up to 6"
Threaded On End
you have to dig it up and then you can use a slip coupling or a extension coupling if you are fixing a straight run of pipe because you don't want to dig more then you have to. If its on a 90 degree then its easy with a coupling and another 90 fitting primer and glued.Before you make any repairs you should call locates first and you might want to find out what caused the pipe to fail in the first place such as improper back fill etc
The male is the threaded end of a pipe and the female is the receiving threaded connecting elbow.
Use a pair of plyers and two small pieces of cork to grab the threaded pipe while you rotate the female fitting. Also, if you don't need the threaded piece anymore, you can use a whole cork inserted into the threaded pipe with a bit of apoxy or super glue.