I have asked this same question quite a few times over the past year.
The answer I always get is that currently existing apps on Google Play will not be affected by the November requirement for API level 26 or higher.
However, Updates (new APK uploads) to existing apps must target API 26 or higher beginning November 1.
I sure hope this information is correct. I plan to leave all current apps as is, with no updates. I hope they are not suspended.
Barry.