I am renovating a house built in 1923 which has interior stucco walls. Am I better off trying to skim coat the walls or covering with 1/4 inch sheetrock? What are the pitfalls of each? Thanks

Hopefully this Title got some attention. I have a 1958 cape cod home with a basement. The basement stairwell has a partial walls on left and right walls going down (to the point where it becomes level with the main floor). So far, just typical walls to an unfinished basement. Now this "hole" leading to the basement from the standpoint of your lateral joists is an obvious interruption to those load bearing points. I am planning on busting through one of these walls on the main floor that sits over the left side of the stairwell. This wall is also the outer wall of the next level of stairs going up. Essentially I want to create a triangular opening on this stairwell going up creating an open look. Hope this is clear so far. My dilemma is that this wall which is studded appears to be holding the upper floor, at least partially. Now, I went into basement well before to check things out and what I see is that technically this should not be a load bearing section but it is BUILT as if it were one. Why do I say that? It has two 2x12s, side by side however they are not supported but instead go perpindicular to the main joists and I can see they were simply nailed in there. So while they look load bearing there are not secured as load bearing joists should be. Basically look like this: I---------I The dotted portion is the piece in question. It does not overlap or anything but instead, just how it looks is nailed to those end joists, yet the upper wall sits on it. Now, somehing to point out that I have identified is the the lower corner of the stairwall, the main stud, most definitely sits on a true load bearing joist and I intend to keep it there. So, my question is should I treat the entire wall as load bearing, despite the design in basement? And second, should I consider putting a steel support column beneath this oddly designed "load bearing joist"? Now, somebody here will know better than me but the overhang from the last supporting joist before this area in question is roughly 6 to 7 ft. So, with 4-5 main joists hanging with last support beam at a 7ft stretch, would that hold sufficiently the weight of a hallway? This is all very difficult without pictures. If that would help, please let me know how to do that. Thanks, Eric Kirk