Sorry that I'm having a hard time getting all this straight.
No problem. It creates problems to envision the consequences for a lot of people, until they understand/embrace the concept of avoiding parallax as the technical goal. Actually doing it helps when that goal is kept in mind. Some subject matter may be somewhat forgiving and with proper software blending we may cover up some shortcomings, but the best chance of success comes with proper technique.
To avoid entrance pupil parallax for single row panoramas (whether tilted up, down, or on its side plays no role) we need to satisfy 2 alignments for the intersection of orthogonal rotational axes at the same time in a single point, and for multiple-row panoramas that would require alignment of 3 rotational axes in a single intersection point.
In the single row pano case, we need to make sure that the camera's Yaw axis and the optical axis (Roll axis) intersect at the entrance pupil position. That requires a lateral shift (only if the tripod socket is not aligned with the optical axis), and a fore/aft 'nodal' or rather No-Parallax Point shift, usually backwards (the amount varies with lens focal length, and perhaps a bit with focus distance). The best way to achieve this, is with a rotating clamp positioned directly under the optical axis (no lateral offset), and a fore/aft sliding bar to move the entrance pupil of the lens directly above the rotating clamp.
With that done correctly, we can happily rotate around the camera's Yaw axis, without introducing any parallax, and stitching will be easy, even with difficult subject patterns. It will not prevent a curved path of image tiles relative to a horizon when we tilt the clamp plane to a non-leveled angle, but straight lines (including the horizon) will remain straight
(not level, but straight) when a rectilinear projection is used for rectilinear lenses and the correct Pitch value is set in the stitching software. When the camera is used in portrait orientation, the vertical FOV is often sufficient enough to avoid the need for a heavier, more complex, multi-row pano assembly.
When we relax our No-Parallax Point (NPP) requirement, everything becomes much harder to understand, and to stitch.