Curious about this...

Take control... declared as defending vs cannot defend

Positive vs negative (negatuive usually wins)

but also

particular vs general (concrete usually wins)

what happens?

My 2 cents for Take Captive winning, but i really can't point to a reason why it would be so...

See Page 17 of the rulebook:

If an effect has the word "cannot" in its description then that effect is absolute and it cannot be overridden by other effects.

i'd say you could take control of Fox Mulder's Elite, but that's it because of the 'cannot'. could sacrifice it though...

The rules state you try to complete as much of an effect as possible, so you would get control of the unit, you would move it to your zone, but it could not be declared as a defender. You could sacrifice it as pointed out for additional effects, but either way the unit is no longer in your opponents so when damage pooling comes around that is two less power you have to deal with.