Convert WP custom plugin for Core PHP Website, Design and Develop custom MVC style website

We have lots of work to be done with the back-end of the current CUSTOM wordpress Calendar plugin and then Convert Process to MVC style core PHP website (no framework). We currently have a basic design and need the bulk of this project to concentrate on converting Calendar plugin to Core PHP. The rest of course includes making a simple admin page to edit contents. We want to convert WP Custom Booking Calendar Plugin to Core PHP using namespace style programming (you must know C++ and or Python) to be considered. We will test you and if you cannot connect to our client database using our database connection string, you ARE NOT QUALIFIED for this project. We will pay per "milestone" that is completed and this ranges anywhere from $100 to $150, as we are breaking down "milestones" instead of giving out on big milestone or one big payment but rest assure when this is all done, it will be good pay day, depending on what you are capable of doing. Now, I am not a developer but I know my way around and know how to give you algo if you are stuck in finding a solution for what our client needs. Things that need to be fixed, among things, fix backend mobile forms (previous gig was to add mobile friendly forms on front end of calendar and now back end needs to be fixed). That is your first task, the following points below, among things, must be done as part of the rest of the revamping of this project. 1. Add PDF on the fly, contracts are made based on current PDF form that client fills from website data. 2. Convert all MySQL statements and fix database queries so that data entry and records are more secure. 3. Add Ecommerce where people can pay for "deposits" and payments due and implement this as part of the contract process and create invoices/payment receipts using PDF. 4. Add Google API for driving directions based and this to the PDF. 5. Make this plugin an API (this may be a separate project in itself, depending if you go this far) [login to view URL] otherwise specified, All Images for website will also use AWS S3 to fetch/store images. 7. Admin page to edit individual web pages and easy way to add additional pages for website.