OK, here is a fun one ... Client wants to reclaim the empty space under an existing curved staircase to use for an extended pantry from the kitchen. The picture is as close as I can approximate the situation since the stairs are finished and walls enclosed.
Have not yet opened the wall but the arrow approximates the location of the new entry that we are considering. In fact, it might be to the right so the entry can be taller.
This will require re-framing the support for the staircase. What ideas do you have to make sure this is structurally sound. I see a header across the impacted studs at the entry point using king and jack studs. Might possibly add some new blocks to stabilize the side studs.
With unfinished stairs like the photo, we supported the stairs, an upright 2x8 under the 3 stairs you will be working on. Draw a level line from the under side of that tread across the next two studs. From those lines measure down the height of header, 2x6s or 2x8s. Cut the two studs at the lower line. Place a jack stud under the frist tread and a jack and king at the width you want the door. Now run a chaulk line from the inside corner (against the drywall) of each jack stud under the other two studs. Draw plumb line up the height of the header and notch them for the header to fit in and and they still maintain the curve.
You may want to find a straight wall to break into it the studs under the stairs will be close together. The one we did was unfinished but I don't think it would be much different. The finishing guys just added a 1x? cut to the curve to the top of the frame and bent the trim, looked good.
Jungle, those are cool looking stairs. Probably not legal (as shown, anyway) by most building codes - safety issue. Villa, if you cut through the wall and saw THAT, it would most DEFINITELY be a safety issue!!!