Hi,
1. Yes, I think that will easily be possible, you'll just have to use the Type of item layout option of your content menu and some CSS code.
2. I think that you'll find some information about this through this
thread
:
You can do it with custom HTML yes.
You can even add it in the description of the product.
It should be like that:
<a href="URL_OF_THE_VARIANT">
<img src="YOUR_IMAGE_URL" />
</a>
where YOUR_IMAGE_URL is the URL of your image, and URL_OF_THE_VARIANT is the same link as the product page link but with the id of the product replaced with the id of the variant (you can get that on the variants listing, via the "manage variants" button of your product page).