Re: Question #7.
See:
This thread on Missiles vs. Torpedoes
Summary of reasons to use torpedoes:
A) They fire every two turns
B) They cannot be shot down by PointDefence
C) Their damage occurs right away, preventing the enemy from firing an extra volley (or two) while you wait for the missile to arrive.
D) They do 56% more damage: 1.25 vs 0.8 (damage per turn per Kt space)
E) Torpedoes can be put on Large/Heavy/Massive mounts, improving their damage factor even more (Massive mount is up to about double the missile's damage per turn per kT)
F) In most mods,torpedoes have a 30% or so to-hit-chance bonus, since a torpedo can seek a little.