OP Firstly you clearly have some skills, but it is clear you have not really researched this product and failed to realise it has no real tangible purpose or practical use.
Also remember, you are up against the likes of major supermarkets, The Works, Hobbycraft etc who all create fun and affordable kids stationery.
The pencil roll shared above is a practical and safer option, maybe you could make a giant version that incorporates a colouring book (both pens and paperwork on the inside) which then has a wide strap a. bit like. rolled up travel yoga mat?
Agree with all previous posters, Disney is a no go.
Facebook is the last place I would seek this type of item, maybe Etsy or similar or set-up your own website, but something like this cannot realistically be limited to just Strood.
With no pun intended, return to the drawing board on the actual product, how it is to be used and photograph it in use. Get professional photographs, maybe send these onto some local art clubs that sell sessions in blocks of 6 or 12 and offer an introductory deal to them per child they enrol. That could get you some initial custom and interest along with valuable feedback. I am sorry I have to agree that using your own child in this way on social media I just nuts, a really bad idea.
I am sorry that your dream here has not quite materialised as you had hoped, but am sure with some revisions and absorption of real feedback you could adapt this into something better marketable and more practical for parents to actually be interested enough to buy into. You have a real creative talent, but obviously need to equal thiss with some business approach if this type of thing is to net you any real profits. Best of luck x