We couldn't remove the old solder after melting it, maybe we need a stronger "solder" sucker. Maybe cutting the leg off will make things easier as Jorgen suggested.
Yes it will do, the package will be acting as a heat sink and drawing away the heat from the soldering iron.
I prefer using solder braid to solder suckers. Solder suckers can drop little balls of solder onto the board leaving you with intermittent shorts
I'd cut the package off, then heat the solder up and pull the leg out with tweezers/small pliers. Often you will find it easier if you add some solder when heating the leg to remove a component.
Then use the solder braid to clean the hole out
