I just took my site from 7.0.0 to 7.0.2 and it was a painstaking process with the move from 7.0.0 to 7.0.1 more than the move from 7.0.1 to 7.0.2. I also just moved a site from 6.1.4 to 7.0.2 and that was a long sleepless night!
The best reccomendation I can say is to document all changes/patches you have done... then go to Unity Market and re-download the most updated code of all your mods.
I had found that the easiest way (rather than do a file compare), is to do the upgrade, then go thru all the modules and re-install them. There are enough files changes using Win Merge to drive a person to the looney bin.
Since not so many mods install clean and require modification of core files, it is best to just do a re-install of all the mods. After 14 years of QA testing, this is the easiest and less hazard filled approach.
If you need assistance, let me know.