If you are going to use Premiere Pro, Adobe has built into the latest versions a proxy workflow that allows you to edit 4K material with low horsepower computers.
See:
https://helpx.adobe.com/premiere-pro/how-to/proxy-media.html
and
https://helpx.adobe.com/premiere-pro/kb/ingest-proxy-workflow-premiere-pro-cc-20 15.html
It basically does what you are planning to do, but does so under Premiere's control so that you can work with the proxies to edit, click a button and see the full rez material for color correction, then switch back to proxies to keep editing. When you are done, you export your full rez master.
A note on switching edit systems -
I switched from FCP-7 to Premiere when FCP-X was introduced and FCS apps were abandoned, and now am very happy I did, my freelance business is based on Adobe Creative Cloud . . . BUT . . . any time you switch editing systems, plan on several weeks of unhappiness, face slapping, and frustration.
The main thing is to not look back at the way you used to do things. You'll be much happier if you just shrug your shoulders and adapt to the new way of doing things.
Premiere has a setting to let you change all the keyboard shortcuts in Premiere to the same as FCP-7. My advice - don't do it, learning the new keystrokes will give you a greater insight into how the programers intended the app to be used.
Premiere is a wonderful edit system, especially because of the direct integration with After Effects and Audition. I am very happy I switched. It is current with all the latest codecs and workflows. But there are many things you could do easily in FCP-7 that do not have an equivalent function in Premiere. And there are also many things built into Premiere that make an editors life much easier that do not exist in FCP-7.
Switching edit systems is like moving from New York to London. If you keep saying to yourself "Gee, in New York I went downstairs and walked 20 feet to get coffee, and here I have to take an elevator, get on the tube, and then get coffee" you will never be happy in London.
MtD