@BenBen I’d recommend finding a theme in the HubSpot Template Marketplace that has the majority of the functionality you’re looking for (most design can be changed in theme settings or overwritten with CSS). This would save on development costs and time to build out the pages.
Regarding your question about personalizing the content / visibility based on the account - this can be done with smart rules (requires CMS or Marketing Hub Pro/Enterprise).
Hope this helps you get started!