Minimizing the use of APFS in Mojave by putting Users and Applications on HFS+
Solution 1:
Consider that if APFS reports checksum errors, and you reformat and reinstall, and the same thing happens again after a short while - then you could very well have a failing storage medium.
Instead of relocating various folders to a partition formatted with HFS+, it would be wise to thoroughly check your drive for errors and possibly replace the drive.
Solution 2:
The user home folder is very portable - you can place it anywhere - on network volumes even in many cases. Same with Applications - they write preferences to the main library, the main temp folder(s) and the user library, but they can exist anywhere you prefer in addition to the typical locations of the apps folder in the root and in the user home.
I’m skeptical you’ll see any benefit and might see less functionality and speed, but absolutely make a good backup and then start making other places to store files that let you learn or control things apart from APFS being the main container for everything added to the core system.
Nothing in Mojave changes the above - you may not be able to delete the default locations, but everything that isn’t SIP protected (all the apps you add later for instance) are highly portable.
You will struggle migtily if you move things the system wants in /Applications and each security patch and update will break as well since they depend on the locations being left alone for system apps and frameworks.