Erza always had that armor as far as i remember. Also why no one noticed that she had a sword, not a spear in her hand?

Exceeds are probably the only beings that have magical power inside them(ie unlimited magic)... but probably they can only utilize it for wings. Nevertheless in the world of floating islands unlimited flight power is great advantage to them... but not against the Fairy Tail.

Wendy should protect them with some kind of wind barrier, or something. She is a Dragon Slayer mage, she could cast ONE spell from time to time(last one i remember was the breath spell about 20 or so eps ago). Protecting Charla with her body won't impress those xenophobic and simple-minded cats(except The Fapcat, seriously - this name is godlike).