Drywalling around tub surround.

Hello! I've seen a few similar posts to this but I'm a newby and wanted to get some feedback for my own specific situation. I want to remove the top part of the wall that separates a big 2-level closet from the rest of the room, to provide easier access to the upper storage area. Having removed a section of drywall, I've found a few studs/posts which I would like to remove. I've indicated them in order of priority: 1 most important to remove, 3 least important. I assume a similar arrangement of studs/posts exists on the right-hand side of the opening. Can you tell me if this is safe to do? I live on the top floor of a triplex in Montreal built around 1900. Thanks in advance, Jeremy.

Hello! Just an FYI: this is my first DIY project so if you read something and want to throw your phone across the room because it was just that stupid, I’m sorry. My laundry room is incomplete, and I would love to get started finishing it. My first question ; there’s a long wall with no pipes or anything that has drywall plus, about every 1-2 feet, a panel that goes from the floor to the ceiling. I’m not sure why they’re there but I don’t mind them... I just need to know how to finish it with them there! Do I just layer and layer and layer a bunch of concrete until it matches up with the end of the panel? (If you haven’t thrown your phone yet I’m proud of you) or do I have to buy something that will snug right in between the panels? I’d probably believe anything you guys tell me, so please be nice! Thank you for bearing through my first post that should probably be titled ‘how not to finish a wall with panels’.