Pounce lets you make a full attack after charging. Could you use the first attack to hit the guy you charged, then use Lightning Ricochet to throw your weapon at someone else entirely for the rest of your full attack, still gaining the bonuses from charging?
RC enforced the concept that you apply any bonuses gained on a charge, that ambiguously doesn't specific one or more attacks, carries on each attack made as the +2 bonus to your melee attack applies to every attack made.
Taking it a step further, do you even have to attack the person you charged?
By intent yes, you must be able to reach the closest space from which you can attack the designated opponent
doesn't strictly say you have to but it is certainly applied. linklord231's quote is about deciding what to do after the first attack, which allows you to attack others if you don't like the result (or kill them).
Could you charge an ally (gaining the +2 to hit and any other bonuses you're entitled to), then just... attack someone else instead?
The rules specifically state opponent, I hope the DM returns the favor and says when the caster casts beneficiary Spells on his allies your Character, a clear enemy, is excluded.
Plus does the attacks and the "secondary target" get the multiplier power attack bonus from leap attack if i'm in a position to threaten him since the bloodstorm blade gives me the ability to treat thrown attacks as melee attacks?
Actually you don't treat Ranged Attacks as Melee Attacks.
You treat your Ranged Attack Rolls
with Thrown Weapons as Melee Attacks. You're allowed to include Feats to determine your attack bonus for each attack, but it never actually says you can apply your melee damage bonuses to Thrown damage rolls. The ability to apply Power Attack comes from an additional clause within the entry. It's specifically added in and not because ranged weapons become melee. Hence why the text says "in addition" and not "in example", and this does limit some things.
And generally (let's say i'm a 20lvl barbarian with no bloodstorm blade levels) if i make a charge with pounce and kill the primary target and he dies can i use the remainings attacks on an adiacent target if of course i'm in a position to hit him without moving?
Yes, Reach weapons can help on this too.