A custom module to change "Ubercart" cart.

Hello,

I need a paid help with building a custom module for my shopping cart.
I need it to do 3 things:

1. As it is now, the buyer has to choose the quantity and then click on the "update cart" button in order for the change to take place -

I would like to have a cart where there is a dropdown menu of quantity that updates automatically
(with Javascript I guess).
the person who chooses the quantity from the dropdown box should see the subtotal automatically.

2. There is a checkbox that if you check and "update the cart" it removes a product from the cart.
Instead of this checkbox, I want a button that says "remove product from cart" (it should of course remove this product automatically).

3. I would like to be able to restrict products for certain amount of purchases for each user. for example -
I want to limit "product A" so every user can purchase it up to 3 times, not more.
I want to be able to set a maximum quantity (for each user) for every product.
If I decide that "product A" can be purchased up to quantity of 3 (for every user),
the dropdown menu in the cart page should only show 1 to 3.

If there is something unclear - I would be happy to explain.

Thank you,

Nik.