Component manufacturers generally do not provide detailed information about their products’ internal construction, in the interest of intellectual property protection. Prevailing industry conditions aside, I would be surprised if a response were to be forthcoming.
That said, much of the information requested could be obtained to a reasonable degree of accuracy through destructive examination; I would suggest obtaining a similar item manufactured without edge sealant to facilitate this process, and a common set of calipers in proper working order. A hot plate capable of reaching up to around 200°C could be used to melt the solder used to assemble the device uniformly, or the device itself could be used to selectively melt the solder on one side.
The most common thermoelectric materials used for this temperature range are bismuth telluride based; the dopant species used and their respective concentrations are perhaps less predictable, though discernable through techniques such as x-ray crystallography. Should such resources not be available somewhere among the chemistry-heavy parts of the UC campus, it’s probable that one could at least find somebody with connections to such there.
As for electrical and thermal resistances, one needs to specify the conditions under which these values are to be measured; being a thermoelectric device, they will change to a notable extent depending on test conditions. While the small-signal AC resistance at 27°C is characterized on page 1 of the datasheet, this value is not guaranteed nor applicable at other device temperatures. Depending on your particular interests, this may be another point of information that you would want to measure yourself.