1.) "mount_mfs" didn't work anymore. I always got:

       mfs: /tmp: Invalid argument

I'll look into this.

   2.) "ps" didn't work anymore. Although I compiled "libkvm" and "ps"
       afterwards "ps" I got "process size mismatch" errors.

That's because your kernel and libkvm are out of sync.  If you
installed a new kernel and updated your include files before building
libkvm and ps, this would *NOT* happen.

   3.) The kernel turned out to be very instable, it crashed half a dozen times
       during reboot, mostly VM faults. I could not even reboot with the old
       kernel because "mountd" caused a panic.

I told people to update mountd.  If you ignore me, you lose.