Creating an extranet-like sub-site

Dear Forum,

I’m looking for advices on the best way to create the following function:
– main website built upon Zerif Pro theme, as a typical “company presentation” site.
– website operated on my own private virtual server, so I have root access to the server
– I’d like customers to:
– logon the restricted area (customer profiles created in the back-office)
– be able to update some profile fields (i.e. password or addressee name only)
– browse through a list of products (<100 products), with sorting criteria + filters
– order delivery of products; actual order is placed on a regular basis, i.e. 5000 items a year, ordering through the website is more like scheduling a partial shipping…
– track “orders”, once I have acknowledge the shipping date
– update delivery status, once the products have been received at the customers’ premises, so I know the delivery is OK
– open / update / track issues on received products through a ticket management engine
– search for an order or ticket using various fields
– extract orders or tickets history (from date to date) as a CSV or PDF file
– on the back-office side: list and extract all delivered order to trigger customers invoicing
– send direct messages to the team (hopefully to congratulate on successful delivery :-))

I first thought of building upon some ecommerce plugin, into which I would hide some features, but need advice on the best plugin for this workflow. Moreover, I don’t know how I could link tickets to orders within the site…

Thanks in advance for any advice!