help for PROXY workflow on FCPX 10.4

Hello,
I am preparing for a future project that would require a proxy workflow, for a sports tv show shot on multiple days.
Here is the idea :

- All shot in UHD 50p, 25p and some 30p (from DVX200s, GH5s, GH4s, mavic pro, gopros...)
1) After each days, MBP copy all shots on a couple of drives, and creates an Event in which it "imports" original footage and organize with keywords (athletes names, multicam interviews, sections for the program etc).
Then we export the event's XML and send it by email.
2) Other computers (pc and mac) converts all 4k footage to 480p h264 and uploads it through local connection or through 4G/LTE (handbrake+dropbox?)
3) The next morning, the editor who isn't on location download event's XML, the low resolution converted footage, and relinks it into his own Library.
4) Once the shooting is over, and we come back with original footage, we replace the proxys with 4k footage for final touches (color correction, reframing/croping, voice over etc) and exporting.


What do you think about that workflow ? Is there anything I need to know to make the relinking/replacing with original files easier ?
Will handbrake works good for converting ? I like that it's fast and we can use it on macs and pcs and convert with multiple computers at a time.
Is there anything I should be warned about ?

woooo wrote: .... UHD....creates an Event in which it "imports" original footage and organize with keywords (athletes names, multicam interviews, sections for the program etc)....export the event's XML and send it by email.....Other computers (pc and mac) converts all 4k footage to 480p h264 and uploads it....the editor who isn't on location download event's XML, the low resolution converted footage, and relinks it into his own Library....Once the shooting is over, and we come back with original footage, we replace the proxys with 4k footage...

While it is theoretically possible to use manually-created external H264 proxies with FCPX, there is nothing built in the product to support it. This would be a science project to investigate, rigorously test, implement and support.

Loading an fcpxml will not relink to files with different names or characteristics.

Here's an article by someone who devised a workflow using externally-generated small ProRes proxies. You could try this but if something in FCPX 10.4 (or a subsequent version) breaks it or it malfunctions, you will be on the line to troubleshoot and fix it: www.fcp.co/final-cut-pro/articles/1794-b...with-final-cut-pro-x

However I think KeyFlow Pro implements some type of custom-resolution proxies for web-based collaboration: www.fcp.co/final-cut-pro/news/2013-keyfl...n-in-final-cut-pro-x