Question about our Creation limit!

Hi guys, I am making a big collaborative game on Core, but I got a few question about the size of our own designed creation.
1: What is the limit size of our Model ? (how many MB is limited?)
2: What is the limit size of our Texture ? (Does the width and height have to be a power of 2? Does the size have to be a square? How many MB is the size limited?)
3: How many MB does Skin parts limited? (parts of the character, such as hands, feet, body)
4: What is the limit size of our Skin animation (how many MB is limited)