I have studied the rites of the ancient pyramid dwellers in some detail and can now offer this summary of their burial rites. The crux of the matter is that, for reasons I have not fathomed, these folk split the body and soul at death.
This mummification process was only performed upon important persons, with the split being more elaborate the further we regress into time.
At its simplest, the body is mummified, removing the organs into four canopic jars. The body is typically decorated with jewellery, an unfortunate habit in that it encourages grave robbers.
I believe that a body double - a replacement for the deceased in the afterlife - is also supplied, which explains grave goods such as furniture.
This theory is supported by the presence of ushabti - images of the deceased - in these tombs. I believe these are replacements for the deceased in the toils of the afterlife and were always constructed from willow.
Food and drink are also supplied. Common clay pots filled with wheat suffice as food, while wine combined with spices is the traditional drink. These would be desert spices, of course, gnomish ones would not be at all in keeping. I have reproduced these from the modern equivalents.
I have also discovered that the name and personality of mummies are supposed to separate over time and must therefore be recorded to ensure the mummy can retain these features.
Thus, records of the name and deeds of the mummy should be present in many burials. as they are recorded on papyrus, these should survive well. Finally, the spirit and shadow of the mummy are also noted as separating from the corpse. I am not sure, however, what form this particular split may take.
It is a traditional tale that mummies may be consulted for words of wisdom, but only if their burial site is undisturbed. Given the rich loot found in such burials, I fear this is an unlikely situation to arise. If it were to occur, however, the historical data available would be potentially vast.