Will the anticipated upgrade from 15 to 16 support these use cases? Or,
should we start looking for alternatives now?  I really want to stay with
openSUSE if at all possible, but I have a responsibility to my users to
maintain continuity of operations going forward.  Is it time for (shudder)
RHEL or a BSD?  BTW, before 1998 we used Sun Solaris and SunOS
starting in 1986.

ALP as it sits now is very different to ALP as it was first announced, alongside the read only transactional MicroOS style distro's that will be built from ALP, the successor to SLES 15 will also be built from ALP which is what Leap 16 will be built from.

So containers won't be necessary, in many cases Upgrades from Leap 15 will be supported and you should expect an experience that's much closer to Leap 15 then that of MicroOS, although it won't be completely the same