When you ran Disk Utility First Aid did you select the volume, the container, or the drive? I just ran a First Aid on a disk formatted APFS and although there was duplication of duplicated volume testing, additional things were checked at the Container level and it appears 1 check was unique to the disk level. Although no errors were reported at any level "postponed repairs" were reported as completed at the Container level.
Based on that I would suggest running First Aid at the container level if not at all three. It might make a difference.
As to Diskwarrior, Drive Genius, and TechTool Pro support of APFS, I am not holding my breath. APFS is a very different animal and Disk Utility > First Aid may, just may, have it covered pretty well and is not leaving a lot of room for the competition to improve upon. Besides that there are a lot of technologies in APFS that have yet to be made available in the GUI or implemented which make APFS a rapidly evolving target.
