Firstly, hi and welcome. I am afraid, though, you many not find my welcome all that warm.
If you want it to look like a serious, binding legal document, why does it look like a menu from a child’s all-you-can-eat buffet?
The very first line reads, ‘xxxxxx believes in simplicity’. Apparently not!
You have to ask yourself, does the world need more low-brow clip-art? Are you qualified, and/or skilled enough to produce good quality illustration?
Harsh, I know, but there is so much bandwaggoneering going on out there with so many unqualified, uneducated, untalented people jumping on board who have no idea what they are doing. They think it’s a cool, easy way to make a living, that the chances of you making a living are fairly slim.
If you are skilled, why are you making clipart?
I may have to eat my words if you are brilliantly talented, but I would advise, strongly, not to enter the swamp as a bottom-feeder. There’s not exactly rich pickings down there. Buy a boat and learn how to fish.
As to the licence, there are loads out there. Pick the most appropriate and then get a lawyer to go over it for you. Can’t imagine it would be that expensive. Alternatively find a lawyer to draft one to suit you. But before you go to any sort of expense, be sure your product has a market.
A good thing to do would be to post examples here for critique. There are a lot of experienced designers hanging around here who will give you honest, fair opinions. They may not always be palatable, but they will be honest and with knowledge and experience to back them up.