Sounds like the engine might be flooded. Next time this happens, press
and hold the gas pedal to the floor while cranking the engine. This will
clear out the unburned gas. Release the pedal and start normally and
it should start right up. Letting the engine sit a minute if it's warm has
the same effect if the flooded cylinder happens to be in a position where
one or both valves are open when it's off.

You might have a leaky fuel injector. Or, if you haven't changed the
spark plugs and wire set in a few years (or 60K miles), you could have
a weak spark.

And tempting as it might be to claim otherwise, no, the seat belt motor
and dome light have absolutely nothing to do with the starting problem.

Bob

Get the engine trouble codes pulled. That should pinpoint the problem(s)
in a hurry.

First, just for the record, cranking and turning over are the same
thing. It means the starter is turning the engine but for some reason it
doesn't start and run. When this happens intermittently, like in your
case, it's either a fuel or ignition (spark) problem. Check for fault
codes in the diagnostic memory. That may direct you to where the
problem lies. Otherwise you need to be sure whether the failure to start
is because no fuel is reaching the engine or you don't have any spark at
the plugs. The other electrical problems you mention are not likely to
be related to the intermittent starting problem. Hopefully the codes
will provide the clue.