There is no easy way to get that shaft off. Some stand 4x4 on end and work from underside. Lots of PB Blaster and getting that pin driven out. Then more PB Blaster and keep on keepin on. Universal joints from Auto Parts store. As for 4x4 stuck. Try removing the electrical wire connection at the from diff. If 4x4 still engaged may be looking at replacing the coil or plate inside which means removal and rebuild as needed. No easy out with that.