Small single-room setup for a one-man band

Hello, First post for me after spending a few weeks reading as much as I can. My needs are not too extravagent, but I'd like some opinions on my setup before building materials and spending a ton of time of this. My wife and I just bought a house and will be moving in later this month. There is a small, attached 'shed' that has been designated as my space for a modest studio (it's actually an upgrade for me - I am squished into a 9'x10' room presently). This shed is 12'14' with a 10' flat ceiling. It is fully wired for electricity, but no heat (Oregon climates aren't too extreme, so I'm not super worried about that). The room is essentially empty with no obstructions anywhere. I've attached a .GIF and an .SDR to show door and window placement (those things on the W and S walls are windows). My extensive Smart Draw skills are in full bloom, as you can certtainly see. How loud are you? Not very. I play (in order of frequency) keys, voice, drums, bass, and guitar (acoustic and electric). I have no amps, everything runs through DI boxes. I bang on the drums quite a bit but relative to most drummers, I am pretty quiet (my music is also faily mellow pop to mild rock in some extreme cases). The shed is on the SE corner of the lot. To the south are railroad tracks with no neighbors nearby, and to the east are 3 vacant lots (the railroad tracks slowly curve into them making the lots unusable for housing). The tracks are not used very frequently so I'm not too worried about their noise, and their intrustion on the nearby lots makes a for nice lack of neighbors in those directions. I would like some level of sound reinforcement because there are people across the street, and I'd like to feel free to let loose and make some noise without worrying extensively about sound levels outside. Details of existing construction The house was built in 1900. As far as I can tell, the walls consist of wood siding exterior, standard insulation, and plywood interior walls. The door on the North has a step down to the floor. The East door is level with the floor. There are 3 windows (shows in the drawing) that are approximately 2' wide and 3' high. Next to the North door is the fuse box for the entire house. The dimenstions again are 12'x14'x10' .SDR is attached Questions 1. Are there any electrical things I should watch for that I'm probably not thinking of? The entire house recently had an electrical inspection and some wiring was replaced - anything special for studio use I should consider? 2. What's the best way to approach wall construction? My realistic options (that I can think of myself) are a)adding a layer of drywall interior (or 2, heck) or b) adding a stud frame with insulation/drywall. No idea which would be more effective, though the fuse box is a major concern with option B. Since I'm planning on reinforcing the walls, would it make sense to do so at an angle to break up the parallel structures, or should that be done after the main walls are in place with floating panels, etc? 3. The floor is concrete. I want something (anything?) else. Would a hardwood floor be my best option acoustically speaking? 4. Since I do not have the luxury of separate rooms or booths, how should I treat this room? Any help or insight anyone can provide would be greatly appreciated. Even though this is a pretty small project compared to many others I see here, it's still slightly overwhelming (mostly because I am in recording limbo until this room is habitable) so I have a new respect for what many of you are going through. I should also mention - my immediately budget is $500-$750 USD for wall reinforcement. Flooring and acoustic taming will have to be handled in 'phase 2' though I'd like to start planning it now as well.