WORKFLOW Issues - Relinking Help

Firstly I would like to apologise as this will probably be a long post.

Let me take you back to when I was DoP on this Indi -feature film. We shot it over 8 months using weekends only. We backed up all the raw files from the DSLR’s and the Audio every week.
About half way through filming it was discussed between the crew about editing. The Director wanted to edit on FCPX (10.2 - he has not updated to 10.3 yet but I have a backup that I have converted to 10.3).
This is now in hindsight, where it went wrong - It was discussed that one of the crew take all the raw files then sync them in Premier Pro using Pluraleyes and he exported EVERY clip as a h264 proxy.
The director has now finished cutting the proxy-exported files.

How can FCPX 10.3 now take finished Edit and use the Raw Video and Raw audio as the Colour Grader wants to use resolve and the Post audio and composer want to use Pro Tools.

Will I have to re-export all the synced files again from Premier as ProRes?
Will FCPX be able to import the raw files and use the EDL/XML from the proxy edit?
(how do I combat the fact the raw audio and video are separate files but in the proxy edit they are the same file).
I hope this is not confusing.

(I have access to Resolve, Avid MC, Premier CC and FCP 10.3)

If your proxy files have the appropriate video TC + reel # , I am quite sure that DaVinci can resolve your problem.
if the editing is not too wild, retimed, etcetera..other wise clean up a bit or add special treatment shot "in plain" at the end
1- export the timeline fcpxml
2- preload original shots in media pool
3- batch synch originals in resolve (or try to load media pool from PPro xml)
4- goto edit page and load time lime fcpxml ( FCPX and DVR must be harmonized ( of compatible version)
5- if TC and reel # are OK it should relink ok
6- export AAF from Resolve

every step will require meticulous QA and maybe clean up but that could work... DVR is often generous in this type of situation. You can even force relink some if necessary
my two cents
good luck

Thank you very much Francois for your response. Apologies for my late response. I will get started on this process right away and let you know how I get on.

Thank you for your quick response Francois. I will get started on your workflow process and get back to you with my results.
All the best