Option 01 · Workable
Clears every threshold. Its only real cost is where it puts the treadmill.
Dashed outline = minimum clearance envelope, 24" each side and 36" in front · shaded = working zones · stair wall at left
Side clearance of 60" on the near side and open floor on the other, both comfortably past the 36" preferred figure. Front clearance of 83", which covers the HFT Pro's full 80" of cable travel with room to spare. Run-off of 116" behind the treadmill against the 96" ProForm asks for. Twenty inches of margin, the thinnest of the three but still real.
Putting the trainer on a 199" wall means side clearance is effectively unlimited, because you have 144" of wall to distribute around a 55" machine. Front clearance is then fixed at 83" by the room's width, which happens to land just past the machine's cable travel. That is the ideal shape: the constraint that binds is the one you have surplus in.
The treadmill takes the back corner, which is the part of the room with three windows and all the light. The two working zones also cross in the middle of the floor. Solo that is a non-issue since you never run and pull cable simultaneously, but it makes the room awkward for two people.
The trainer's exact position along that wall is set by where the small side window falls. Measure from the stair wall to the near edge of that window before you fix it, because an 82" tower will cover it.