which properties would you try to match for purposes of product identification?
You should rather use measured bp's from the literature, or if possible perform a atmospherical boiling point test.
Calculated vacuum bp's can be very different from real world data, and should only be used to give a rough idea about identity.
is index of refraction at room temperature a good identifying trait?
Yes, using a good refractometer, and performing the measurement at the same temp as the literature reference value.
The traditional way of identification has always been to measure the melting point of the substance (or of a derivative if it is a liquid). See for example Post 443176 (https://www.thevespiary.org/talk/index.php?topic=7999.msg44317600#msg44317600)
(Rhodium: "More articles about Ephedrine/Pseudoephedrine", Stimulants) where they identify the products through reporting the melting points, boiling points, density, refractive index, specific rotation, solubilities, crystal shapes, elemental analysis, and even the mp for 3-7 different salts/derivatives of each isomer is presented (where applicable). It takes time and patience to identify something with 100% certainity.
TLC can usually also be used to give a good hint of identity, especially if you have a reference sample to compare with.
If all identification tests are inconclusive, but you have verified by TLC that you have a pure substance which is dissimilar to your starting material, then assume that you have gotten your desired product and continue to the next step in your synthesis. Then see if you can prove the identity of THAT substance using any of the above methods, and if you arrive at the conclusion that you at that point have the substance you should have, then you can assume that the intermediate also was the correct substance.
Proving the identity of any substance without sophisticated analytical equipment is a hard task, and you usually need to combine clues from several methods to be able to determine anything with a good degree of confidence.