Submunitions questions

Hi, just a few more newbie questions:

How exactly are submunitions targetted?

Relevant to the topic of Gunboat vs Gunboat where
there are a huge number of 2 mass and 4 mass ships
about, can the submunitions target multiple ships?
(My limited understanding says no.)

Can submunitions target fighters?  Is the bulk of
the cost of ADAF and PDAF the targetting systems
rather than the actual weapons? Can the submunitions
missile target fighters?

Could you purchase one-shot fighter defenses?  At
1/2 the normal cost?

I'm a bit confused about how the Electromagnetic
Pulse missile is supposed to work.  Isn't this just
incredibly more effective than the needle missile?
The needle missile disables a targetted system 1/2
the time, where the pulse missile has about a 1 in 6 for
every single system.

Granted, the needle missile damage is a little more
thorough and can't be repaired but still...

Does the system the needle missile is targetting have to
be designated during launch?  (My guess, yes.)

Michael Sandy