The knob handles you removed engaged the strike somehow. Some go through the strike, some grab some ears on the end of the strike. Once the knobs are gone it should be fairly easy to engage whatever to pull the strike back. Push the door closed as much as possible, really pressure it, to get the bind off the strike. I cannot think of anything that will really stop a strike bolt from moving, but they can be wedged in the strike hole.
I think I noticed that the door you're struggling with swings toward you. If the above doesn't work, you should be able to get a knife edge between the door and jamb to lever the strike back into the door. Again, push on the door. This is hard on the knife and you can break the knife blade - use caution. Try the knife blade trick on some other door to practice so you know what I'm talking about. A sawzal or hacksaw blade can be used the cut the tip of strike off. You can gently pry the between the jamb and door and spread the gap until you can force the door open.
If the door opens away from you, you can remove the door stop on the strike side of the door and insert a screwdriver, crowbar, or similar to lever the strike.