I dont make the rules... just try to help sort the mess. Any help from the community is much appreciated.

The feature I am on started in FCP7
-Transcodes from RCX to ProresLT 1920x1080
-Logged and sync to dual system sound in FCP7 with PuralEyes and some manual syncing
-Bins organized by scene with the new sync clips, no sequences, no multicam clips

With 3 weeks of shooting down and one week still to go, the editor that was just hired is Avid only.

My questions are:

-What is the best way to transition to MC5.5? Automatic Duck? I've watched a couple of help videos but they all start with sequences transferring. I am more worried about all the time I've spent logging and syncing to new master clips and the bins transitioning over. Will that stuff transfer? I can deal with logging again, I am more worried about the sync.
-If all the files are ProResLT, will there be any issues when it comes to online and linking back to R3D? I imagine it will be a DPX online because it is heavy in VFX.
-Should I transcode the last week also to ProResLT to keep all the media consistent? Or should I transcode the last week of production to MXF? I don't particularly want to have mixed media if I can avoid it.
-Any known hiccups in the Automatic Duck transfer I need to know about?

Any workflow issues people may have had doing this before?

OR
Do I throw up my hands and spend 2 weeks retranscoding to MXF and starting over with logging and syncing in MC5.5?