I would transcode everything to 720p 59.94,(Apple ProRes LT) it’s what you will get on the set, so everything needs to be in that format in order do reduce any renders time.
Create in compressor a droplet to automate this conversions.
Identify really well all your files, it will save you a lot of precious time, create a good folder structure inside your hard drive and inside Final Cut.
Simulate what you think it will be your operation on set.
Good luck.