Adding a subdomain in Webflow (w/ e-commerce twist)

Hello Webflowians.

I recently started a vitamin brand, with the domain www.vitaminbrand.com (hosted on GoDaddy). We are expanding into CBD. I want to give CBD more of its own platform and would like to do cbd.vitaminbrand.com (keep it under the current brand visually, just add better landing pages that are relevant to CBD). I can easily create the subdomain in GoDaddy, but need to create the subdomain pages in Webflow. Do I need to create a new project for this with new hosting costs?

Another question is how the store will connect. I would like them both to share the same cart (which is through Foxy.io) as well as product pages, so CBD will be on the vitamin product page, but vitamins probably won’t be available on the CBD, just a link to the other pages.

Am I looking at this the wrong way? Should I consider something different? Of course SEO is my main focus.

Best,
Emilie

Here is my public share link: LINK
(how to access public share link)