Great idea on the cartoon creation!!
You should be ok for the media that comes with FPSC because they implied no restriction unlike thier 3d game maker product, and the company, conitec's 3dwc game maker.
You will of course need to have a license (rights) to any media you put into FPSC from external sources like model, grahpics etc...
And you can't make a simpson's cartoon, (unless you own the right to the simpson's)
I had a similar idea of using it to create screen shots for other projects of mine where a 'scene' type graphic is needed.
However I just finished working for an amusement company in May and was able to pick up a cheap MS-PACMAN for 35 bucks.
I now have a mini-PC inside the cabinet now and is awaiting WindowsXP embedded to come in the mail.
When finished I'll have a good test bed for my idea of using FPSC to create an arcade game better than my current DOS based flight sim arcade game.
Good luck on your cartoons.
Rocky Raccoon