handles, lock, and the strike plate
Our 82-030 can replace the handle set with the top-mounted thumb lever without adaptation as long as there is an offset locking bar behind the thumb latch that engages with the mortise at the center of the handle set.
What's confusing is that the original handle doesn't look like it has a centered latch since the thumb lever itself is, for whatever reason, mounted above both screw holes. The reality is that when that thumb lever is turned, an internal arm mechanism reaches down the spindle and turns it. I recommend removing the handle set to confirm that this is the case.
Our 82-030 works the same way but its thumb lever is centered already. It doesn't need that additional (and redundant) arm mechanism.
Unforutnately, we do not carry a suitable replacement for the mortise lock shown in your photos since the locking hooks are oriented differently than our parts. We apologize for the inconvenience.