Question 1: The DM forgot about the invisibility potion. Stupid DM. 
Question 2: If the ogres are unaware of Blasco, they don't threaten him, of course. And in fact you never threaten an enemy you can't see as far as I know, so no AoO or anything. Also, given the invisibility, you tell me where Blasco is (in threat range of an ogre or not).
Sorry about that.

Question 2: If the ogres are unaware of Blasco, they don't threaten him, of course. And in fact you never threaten an enemy you can't see as far as I know, so no AoO or anything. Also, given the invisibility, you tell me where Blasco is (in threat range of an ogre or not).
Sorry about that.