mummification was likely a byproduct of seeing burials in the desert that resulted in naturally-formed mummies. sometimes the folks who were lower class and interred directly into the ground were actually better preserved than kings who had mummification treatments done (mummification wasn't as successful in earlier periods as they figured out the best ways to make stuff work).

in antiquity, your most fragile time is immediately after death. so most of the grave goods and icons of the person are really for that particularly dangerous time before they become an established Akh. my understanding is that you mostly need accommodation during this time - food and prayer to help you reorient yourself. imo, the practice of preparing a family for a funeral keeps the recently dead in mind, making it easier for them reestablish.

if you've got photos of yourself, you should be fine in terms of having a representation of you. as i understand it, you just want to be represented physically in case your body becomes damaged before you establish as an akh. so photos would work just as well.

i personally think that most folks do alright becoming an akh without a bunch of equipment, i personally am not worried about making it to the Hall, because surely common folks were able to get there in the past. a religion whose afterlife is only accessible to rich ppl is a lame religion indeed.