Hi, as you can see from my profile, I have created a lot of Chrome\Firefox extensions. The last one I've created for my client deals with Amazon (exchanging some data from Amazon orders to an order tracking system and vice versa), so I sure know what I'm doing.
Regarding your project, I think it's not necessary to use Amazon's API, as all of the mentioned data can be gathered from the product page itself.
I understand every part of your project description, and I'd like to see documentation for affiliate network API, and design specification before starting the work.
Regarding Safari extension, I could do it, but to be able to create an Safari extension, you need to register for developer account on Apple website, and pay for certificate which costs $100. So if you can take care of that, I could do it.
My current offer is only for Chrome and Firefox versions.
Regards, Stefan