Ah, so all shinigami death weapons in YML have to be from within the time period, yes? Not like lawnmowers and other things in the canon?
Do you have to own the companion of your character? That is, if you have, say, a shinigami, does it have to be companion-less until you obtain a second character, or can it be companions with someone else's character? If it can, does your second character also have to find a companion from someone else? That means if you have one shinigami and no other pets, you can never have a demon since demons are only with humans, correct?
It said that dolls are the only class that physically age. Does that mean that the humans do not in their art? Is this because Dolls age in a shorter amount of time than humans?
May I ask why it mentioned 'his/her' in the shinigami FAQ? Also, shouldn't it be mentioned somewhere there that there are no female shinigami in existence at this time?
Do demons always have to be butlers/maids to their masters, or can they pretend to be parents or guardians of some sort? For a lower-class citizen to have a butler or maid, wouldn't that be somewhat awkward/conspicuous?
I know that demons each have an animal form and that the animals are traditionally black, but does the animal chosen have to be naturally black, or can they be presumed to have a case of total melanism? For example, would a black peacock be considered okay, even though black peacocks are either extremely rare or possibly non-existent?

- Yes, they do.
Yes you need to own your companion. You cannot be a companion with anyone else's character.
Doll aging refers to when they become oversouled, not literally age. Of course, humans will age but I doubt it would be very noticeable.
It is mentioned in the Kuroshitsuji Wiki that there are no known shinigami. The "his/her" was a formality.
Yes, demons always have to be maids or butlers.
The animal doesn't matter as long as it's black.
- Punani chans