Good start on a list. It is clear that the two isotopes are so very different in nuclear properties that they should be considered different elements- yet the chemical properties are identical or similar - so the profound nuclear differences are masked by chemical similarity.
To add: one nucleus is Bosonic, the other is Fermionic. Boson statistics are probably the biggest difference of all. Near-field charge of the nuclei is another. NMR and magnetic susceptibility you mention. From: David Roberson Jones, since you mention how different protium and deuterium are perhaps it is an excellent time to discuss the differences: Obviously the mass of deuterium is approximately double that of protium. At the same temperature protium would be moving between collisions at around the square root of two times faster. Deuterium is physically larger than protium but the size difference may not make a difference in the chemical behavior directly. Here I am referring to the nucleus and not a neutral atom. The magnetic properties of the two should be different but I leave that decision up to others with an opportunity to look into the issue. The spin differences must be important. The behavior of each of these isotopes to electromagnetic radiation would be quite different due to the large mass to charge ratio variation. Deuterium can combine with another of its same isotope to form a stable nucleus whereas protium generally does not. This may be the main physical difference affecting LENR behavior. Deuterium can supply a neutron to any nuclear reaction that protium can not. The proton and neutron can be separated and individually expelled under certain conditions. I suspect that protium diffuses more rapidly than deuterium through metals due to its lower mass and perhaps smaller physical size. I have barely breached the list of differences and I am confident that others can correct and improve this beginning. Take a moment to add factors that you may have knowledge of that clearly pertain to behavior separating these isotopes. In his Arata replication, Ahern found that an alloy of mostly nickel with less than 10% Pd takes up more hydrogen than Pd alone. But he also found that hydrogen concentration did NOT correlate to excess energy. However, this was with protium, not deuterium. The highest absorber was not the most active and a low absorber was actually superior. There is a known correlation of excess heat to deuterium concentration in Pd-D experiments, which is completely absent in Ni-H. This is yet another reason, one of many - why consideration of all the evidence, giving no preference to Pd-D, points to many different routes to gain in LENR. In many ways, protium and deuterium as so extremely different in physical properties (especially nuclear properties) that they should be considered to be different elements instead of isotopes of the same element.
