Media management stability (and messing with proxies.)

I´m just preparing a project with 100+ hours of footage and have had some difficulties with FCPXs media management.
I´m mainly shooting Blackmagic ProResHQ Flat so the color correction will likely be done in Resolve. Because I had some issues with relinking in Resolve I decided to work with the original footage in FCPX so in the case the relinking does´t work I can still XML to resolve importing the source media.

As I had already finished generating proxies in Resolve, when the decision was made I messed around with relinking in FCPX and discovered some things:

I imported all the original footage into FCPX, then relinked quite some clips to the external Proxies generated in Resolve.
This worked well, when the proxies had the same name, image size and audio channels.
After doing some work roundtripping to and from Plural Eyes, when I wanted to revert to the original footage suddenly some clips couldn´t be relinked.

I had not modified anything in the source folders on the HDD. Neither with the original footage nor with the external proxies.
Somehow I had a hunch about the imported project-sequences from Plural Eyes and when I deleted them, I could relink to the original files without any problem.
I could´t yet reproduce the error but here is what I think caused the trouble:
Normally I would create a project in FCPX, XML to Plural Eyes, sync and XML back to FCPX. Like this I will only work with the references to the source media as FCPX knows it.
But on one import I imported the footage to be synced directly into Plural Eyes and XMLed to FCPX.
This somehow created a second instance of the source footage which confused FCPX.
Though this is quite a special and non-standard case it should not happen.
If there was the possibility to force conform source media I would be okay with it but there isn´t.

And to the "messing around with proxies" part:
I started relinking to the proxy footage because many of the more important clips are already color corrected quite nice.
I thought I could trick FCPX into generating it´s internal proxies from the external proxies to keep the color correction.

1. Relink to the external proxies
2. Generate proxies within FCPX (quarter resolution is nice for me and I have the color correction from Resolve)
3. Relink to the original footage
4. Start editing with the proxies, being sure the original footage can be referenced in the end.

Unfortunately on relinking to files with different time stamps, FCPX discards all existing proxies. Actually they are stored in subfolders named after the creation date of the source clip.
And I haven´t yet found out how to tell FCPX to use those proxies without first generating new ones.
Any ideas on how to get my color correction from resolve into FCPX without loosing the reference to then original (flat) source files are appreciated. But this is not too important to me. Would just have saved some time later.

What worries me more especially after reading www.fcp.co/forum/4-final-cut-pro-x-fcpx/23580-bye-bye-proxies
is what happens if I have to rearrange the source media later.
I will make some test during the next days and post my results.