If you did bring the wall down lower, then you could wrap the stub wall with a few pieces of trim to look like your post and drop a 1x to but into. Looks kind of cool.
This is the main staircase, located in the back of the house that you may be finishing. One side goes up, the other side goes down and there is some space between the two. To the right of the staircase will be 5 steps going down then out to the back patio. To the left of the staircase there MIGHT be a second entrance onto that same deck. Depends on cost.
If the left side of the house continues to be "longer" we could reverse this staircase pushing it toward the gym further and having the downsteps and railing abut the hallway down to the back steps and door. What this does is remove the wall abutting the gym and make it open to the staircase. The 1/2 bathroom/laundry or 1/2 bathroom/elevator shaft would now abut the bedroom on the back and right of the 1st floor.
Here is the main staircase which is being relocated facing the hallway in the back of the house. It will go upstairs and downstairs. There will be eight stairs, a turn and then another 8 stair up. A second turn may be required depending on where it arrives on the second floor. Please note that this staircase, like the front foyer will have a shaft to the second floor!