>1) Actually kill the remaining bees using ? Soapy water? Drive them out
>using beegone? And then totally seal up the hive until the spring when I
>install a new package. Put moth crystals in the sealed hive.

Moth crystals would render the honey unuseable that was left behind -- I
assume you were going to extract what you could first and allow it it be
robbed out before putting in crystals?

>2) Kill the remaining bees, extract the honey that is there, seal up the
>hive with moth crystals in place.

Better, honey is extracted.  Fumes could drift to strong hive and kill them
too.

>3) Kill the remaining bees, put the deep hive bodies on top of the good
hive
>and let the good hive take care of the honey and wax moth problems.

Possibly the best option, but depends on how long till your honey flow is
over.  If over now, you could combine using newspaper between, after killing
the weak queen.  If you have laying workers, that would most likely not be a
good idea.

>4) Just seal it up with moth crystals in place and let the crystals kill
>everything.

Again, this means you have a large amount of potentially deadly honey in the
spring -- which your strong hive might rob out and suffer as a result.

>What do you suggest?

Assuming there was no disease present and there is a queen laying, why not
switch the two boxes after the honey flow? This would lead to influx of
foragers into the weak hive.  Or simply combine the two hives and have one
for the winter (let the strong hive clear out the wax moths).

In other words, FIRST, determine why that hive keeps having trouble, before
contaminating the strong hive.