WordPress: sell and deliver four browser-based html applications

We sell digital products through WooCommerce and are launching a browser-based application in four editions. Each edition is a single self-contained HTML file — no server or database. Free demo versions are already public; the paid full versions must reach buyers only.

The work

Integrate the four supplied application html files and install the supplied WordPress plugin.
Create nine WooCommerce products: four app editions (£59 / £59 / £49 / £49), four app-plus-downloads bundles (£89 / £89 / £75 / £75), and an additional-user option (+£25). Merge two older bundle WooCommerce products per edition into one and retire the rest.
Apply our existing 12-month access mechanism to the new products — it's already configured for other products, so nothing new to build.
Add a section to the My Account dashboard with the new html files and access to them.
Protect the paid files: logged-in purchasers only, not guessable or directory-listable, excluded from search engines. The free demos stay public.
Checkout: add a required, unticked consent checkbox (immediate access, waiving the 14-day cancellation right), and disable an existing coupon.
Point twelve buy buttons on four static pages at the new add-to-cart URLs.
Test the full flow: purchase, dashboard, opening each app, logging out and back in, a second device, expiry, and that a non-purchaser can't reach a paid file by URL.

Note: WooCommerce sits on a Wordpress subdomain while the application HTML files are on the main domain, so a plain login check won't work across the two, ideally we want the wordpress login to existing dashboard to allow customers to login. Tell us how you'd handle it.

In your reply, please include: your approach to protecting the files across the two domains; whether saving user progress to the customer's account is included, optional, or excluded (it currently saves per browser); a fixed price and timescale; whether staging is included; and two examples of similar WooCommerce membership or digital-delivery work. Ignore the estimated quote, I will pay to have it done quickly and correctly.