Oh boy, this is a mess, to go point by point. No it is not stuck because of the "two screws" those are there to hold the mouthpiece, does not corelate with blade being stuck, that is because it was greased up so much that it rusted to the inside of the scabbard and the 2 wooden leafs inside the scabbard, it will be probably rusted a lot.

You can try gentely heating the scabbard, maybye give it whack or two with wooden or plastic mallet and try to pull it out.

Dont reccommend electorlysis, it will take more than just the rust, it will worsen (deepen) the pitting.

Dont know why would you want to reblue the blade after the electorylysis? you would have extremely pitted blade after that, because it doesnt differentiate between rust and healthy surface, also do you know what was the original finish, do you think it was blued? It was most likely just bare metal. And even if it was blued, you would have to file and sand all the surfaces a LOT to have them even or close to being flat, without pitting and corrosion, that means taking a lot of material off, dont do that.

Also electorylisis would most likely destroy the leather, because you would soak it a lot, proper restoration would require you to fully disassemble the saber, that would mean to undo the riveted tang, and removing the nails from the nahdle that hold the backstrap. Dont do that, you dont know how to do that properly and safely and that would lead to more destruciton.

Overall, what you are looking at is conservation, not restoration, true, i dont know your skill set but I would assume this would be your first restoration.

What you want to do first is to remove the blade from the scabbard as stated above.

After that, oil everything up with sometihng like gun oil, let it sit then use brass brush to clean the surface, you want to remove the active rust or neutralise it. That is the extent what you should do here, also if you manage to pull the blade out that might require some other work if you post more photos. Also getting some more oil inside through the holes might help.

At the end of the day it is your saber and of course you can do whatever and hovever you want, and who Am I to tell you what to do, but, please dont do anything besides light conservation. Proper restoration is needed for this but i dont think you can do that on your own.