A website written in PHP5 to be updated to current standard on its new server

I need to move a working website from my old server to a new cloudbased server. The new server is in place and a copy of the site and data has been transferred.

The website in question is a well established subscription service for film makers. It is effectively a database of the planned music for a film/TV show in production. Its use recently has fallen off as the site has failed to move with the times but it continues to have a few subscribers who do tend not use the more creative functions the site offers but instead simply use it to word processor their notes... typically cue descriptions, organised in Reel/Act/Timecode order.

Each user has a secure password-protected login and is assigned either an admin, editing or view-only status for any given film project. That determines what they can see and edit within the site.

My plan is to get the site working on the new server initially simply to offer that basic word-processing functionality. So...
Firstly I need a professional to check that the server is set up correctly (ie the databases are in a logical place, that the code is accessing this local data and that the server is nicely secure.
Secondly, to get the log-in procedure working for the various categories of user, such that they can view or use the basic word processing functionality of the site. (the display and edit pages ...see the attached pdfs).
Thirdly I need the code to the existing 'display page' tweaked such that it works with the latest version of PHP, if necessary with the removal of any links to those areas of the site that are no longer functioning under the latest php.
Fourthly, I'd need the 'edit page' and some of the admin pages similarly tweaked to allow data to be written to the display page and subsequently edited, and also to allow users to be managed by each projects 'Admin user'.
Finally, once the above is working to my satisfaction, I'd then need help to coordinate the transfer the latest data from the old server and repoint the domain name to the new server.

The above, on the face of it, might be very straightforward and, once the log-in stuff is fixed, it might just work as is. But I'm sure the right person will very quickly see any issues with the old code and will be able to get it working.

Longer term, getting the above achieved will buy me the time and confidence to shut down the old, dying server, and then commission full rewrite of the complete site on the new server utilising the latest code and practices, not only to replicate what functionality we already have but also to introduce many new features. The person who helps me with the above tasks will be well positioned to become the person that undertakes the full rewrite. So there is the potential to establish a longterm relationship with what could become a vibrant and popular site.

An understanding of SMPTE timecode ie hh:mm:ss:fm would be useful, as well as an interest in movie, TV and music production.