Ask HN: Talk a solo founder through the high level stack to build

I'm a solo founder who has built the prototype and pre-MVP all by myself. I build (MS/BS CS)/hustle/hack well. This is a niche product, and I will not go into recruiting issues here. Users are itching to try the product, and I wanted to talk through the high level rough (correct) steps of the v1.0 build, and get input on best practices.

The objective is to build a minimally featured end-to-end system. Users can sign up, create an account, pay, and access the core technology that is hosted on the cloud. The core technology is a separate component that is not part of this discussion.

Specifically, this pertains to the website and everything that goes on behind the scenes during a user interaction.

Key considerations: this needs to scale, be reasonably quick to implement, and secure so someone else can take over at some point. Also assume that UI/UX design is ready. I expect that this will take time, which is fine.

I'm going to start this discussion with the first steps:

1) WP to get the front end up: 1-2 days 2) Flush out landing page: 3 days

Right away I know I'll need one or more of php/js/jquery and mySQL, and integrate with payment processors and gateways.

Thoughts, best practices?