@Adrian N , Apologies for the delayed response here.
1/2:
You can have multiple sites as sub-directories. Something like, site/app1, site/app2, site/app3.
Please see Virtual applications and directories
You can change the 'Type' to 'Application' in the Path mappings for /folder.
On the Publish dialog, you need to choose the appropriate virtual App. Then you need to include the virtual directory path in the “Site Name
” and “Destination URL
” sections on the Connection tab.
Please see this old blog on deploying multiple virtual directories to a single Azure Website
https://learn.microsoft.com/archive/blogs/tomholl/deploying-multiple-virtual-directories-to-a-single-azure-website