[jayd]

Hey, in case you see this---when you do cartoon figures don't try to think in terms of standard human anatomy--in these types of creation you are allow a certain "suspension of belief".

go back and study how thumbs are made---if you remove a thumb from a hand, most people will just remove the digit but the thumb actually extends down to the bottom of the hand and looks eerily like a chicken leg quarter. Look at your own hand and you will see. This "leg quarter" is what makes your thumb opposable.

now, to your figure--thumbs rest on the inside and not the outside to take your inside most finger and change it to a thumb.

You don't have to do much else after that---a three fingered one thumbs character is not all that uncommon--hope that helps with the hand if you ever actually see this, LOL. best wishes!