A.) With cards like Ice Barrier, "Secret: As soon as your hero is attacked, gain 8 Armor." spellpower will affect this (being a secret card) so am I correct in expecting it to increase the armor value?

No, Spellpower does not affect armor gained. Healing is also not affected by Spellpower.

What is the order in which card effects go when more then one card has "do X at the end of your turn"?

Timing for minions that trigger at the end of a turn are based on when they were played. Whichever minion came into play first triggers first.

If I have a spellbender in play and my opponent uses power owerwhelming on his minion does a 1/3 become the target of the spell and die at the end of my opponents turn or die at the end of my turn?

The Spellbender triggers and becomes the new target for the Power Overwhelming. The spell just requires a friendly minion for the original target. Since it's still a spell that targets a minion, the Spellbender will be activated.

What happens when the new freezing trap triggers on a 9 cost minion like alexstrasza would it be 11 cost and be unplayable forever?

Yes, her cost would become 11. You would need something that would lower her cost to something that is a playable number. Freezing a big dragon makes an equally big glacier.

If I Counterspell a card, does it still trigger cards which have a "when you play/summon a card" trigger, like Illidan Stormrage?

Counterspell only counters spells played by your opponent. Minions, hero powers, and minion abilities (including Battlecry effect) are unaffected by Counterspell.

What is the order of execution of secrets?

Similar to end of turn effects, Secrets will resolve in the order they were played if they have the same condition for their activation.

Ask Phenteo/Zeriyah/Eldtyara <Part 2!>