Humans share 98% of their genes with pigs so you probably can apply all same method to humans as they apply to pigs.
most likely taste is very similar as well except that humans are only skin and bones so there will be very little to eat.
cooking technology is obviously same as cooking pork and nobody can even tell the difference in taste since when you cook something it is all about seasoning and spice if you sook it without seasoning it will be pretty horrible.

I guess you could salvage some edible components from hands and legs. Vagina and womb also should be pretty tasty

blood stains do not pose any aesthetic problem it is pretty easy to wash but if you are concerned about leaving evidence probably you should just spray everything with some iron-containing salt what will conceal blood making everyone look like big blood stain of you can get some luminol and check for leftovers. you will not be able to clean everything well enough because any trace amount of iron will be visible. Iron is very sticky and hard to remove as you know about rust stains