Theme or Set Up Advice for limited amount of products

I have a website with just a few products, most products it will ever have will most likely be less than 20.
I need the cart functionality mainly for checkout and payment with Amazon features.

Is it possibly to simplify the system enough so I don't have to redesign my entire site to work with opencart templates?

For instance.. each product has its own page background graphics, slideshow, youtube links and so on.

Any suggestions on the best way to handle it would be appreciated, I don't want to get into full custom template design if I can avoid it, at least for now because its becoming a time sensitive issue.

well, installing OpenCart is a time sensitive issue, there is no shortcut way, to do such.
You either have to decide on using OC, or then, try to find some Javascript Supported simple Cart Software,
if you want to combine you existing Content, with some kind of a Cart-setup.
The latest OpenCart v.2.3.x Versions would basically offer a way, to do such, as you plan,
but it will still take some time, until this is gonna work, probably most DEV's don't even know yet, how
it will have to be done right.
Good Luck
Ernie

Can you provide a link to your current website so we can see exactly what you need?

you can start with any theme and get quick install from that theme.
quick install comes with all option configure by it self.and you have to do minimum work on that

Thanks