. First off, welcome and this character looks very interesting for it to be a cat^^ (mind you, I'm a huge cat lover
Anyway, here are some other pictures that could help out some:
Okay, on to your questions. Now, I'm going to ask, do you have a local donation thrift store like a Goodwill and Salvation Army? If so, go into the winter clothing section of the store and find something of that style. When you find it and if it happens to be a solid white with no designs on it or whatever, go on and get it. All you would have to do is turn that solid white into a purple with fabric dye.
However, when you find it and if you can't find it in the color that you need, then still purchase it, but you're going to have to create it from hand with cotton or broadcloth fabric. Just an fyi, those 2 fabrics are incrediblely cheap. I know you want to avoid creating the coat by hand, but from what I can tell, that might be your only option. Also of course if you can't find the coat already made, then you'll have to find a pattern that's similar and create the coat from scratch.
So for your sake, I hope you find the coat already made and whatever. In terms of the buttons, you can always create fake buttons and just base them on the coat itself. Just to give an illusion without the hassel of creating actual buttons.
The second item is the hat. Just by looking at it, it's a purple small top hat with the rim flipped up a little. Not alot, but just enough to where it's not considered a pirate hat. Since Halloween is next month and Halloween stuff is now in stores, go to a local WalMart, Dollar store, a specialty party store like Party City, and a specialty Halloween store. Just look around and see what you can find and try to find it in that purple color you need. Of course you'll need to tweek it by adding that little mark he has. If worse comes to worse, find some purple cotton fabric and just cover the hat with it.
In terms of the claws, they look like very large fingers. You can create some gloves, take 2 fingers each and create 1 claw from them. Just make the thumb a separate claw. With the claws, up to a certain point of the gloves, create the tips out of air clay. Once the clay dries, use Wonderflex so it will prevent breakage from the clay.
Anyway, I hope this helps. I'm sorry if I was confusing or I didn't make any sense. Good luck