Embellishing is just fine with me.
I did find some interesting information on matagots if it helps. They've clearly got some influence over luck and a sheer knack for producing money. I always wondering in cases like this where the creature got the money from. X3 Based on the choice of wording, I'm imagining it's either magically created, the cat can teleport, and/or it's one impressive burglar or gambler. That and the matagots are described as "walking into the mysterious places of the night", which is very interesting.
This link describes them as magician cats, which makes sense if we considering how some versions say it is recieved when a wizard sells his soul. It also mentions that stroking one will bring money and health. Apparently, Puss in Boots might be considered one as well.
This link provides more information on cat stories in general, some of which appear to be partially real. Although perhaps the most relevant part of it is this section: "Superstitious Cats: "Matagots" or "Magician Cats" were said to bring wealth to the home where they are well fed. According to French legend, a Matagot must be lured by a plump chicken, then carried home without the prospective owner once looking backwards. Then, at each meal, the Matagot must be given the first mouthful of food. In return, it will gives its owner a gold coin each morning. In England, Dick Whittington's cat was a Matagot who brought its owner good fortune and changed his luck from bad to good."
Hopefully some of this will be of use to you. If you'd like, you could even expand further on matagots by combine every black cat superstition possible that you feel fits with your visual.
Of course, all of this just makes me want a kitty.
Cats are so graceful and playful. 
/unashamed cat lover and probably a future catlady
I personally am also a fan of cats. The new FAQ page is very helpful!
