Python ships with RH6, and includes a working sqlite3 module.  So if you are restricting yourself to software directly supported by RH6, you are fine.  If you are installing python3.6 on your rh6 box, then you can also install a more up to date sqlite in order to get it to compile the sqlite3 module.  So I don't see any actionable issue because of RH6 here, either for us or for pysqlite.  The other issue is a different story, of course.