[White Council] When the White Council attacked Dol Guldur...

[lathspell]

He[Gandalf] says that the White Council was deceived. He says that the 5 of them drove the Necromancer out of his fortress in Mirkwood. Just by the White Council's presence? I dont think so. The Council would not have been deceived if the Necromancer just fleed from the attack.

This quote from Iarhen gives answer to most questions asked here.

Gandalf speaks about the 5 of them driving him out of Dol Guldur and he speaks about the White Council as in the way that the White Council are those five people. Radagast, Saruman, Gandalf, Galadriel and Elrond.
The same line explains that they were with the 5 of them, so no armies were brought there.

Iarhen - I think it can be explained otherwise. You say The White Council could not have been deceived if Sauron fleed from Barad-dur. But Sauron didn't just flee, it was more like a tactical drawback to Barad-dur which was his stronger fortress. He knew their plans, that they were going to urge an attack on Dol Guldur, trying to capture/slay (I do not know) Sauron. Sauron wasn't ready for battle yet, he was biding his time, searching the areas were the Ring was lost. Knowing their plans, he just decided to go back to his old fortress, leaving the Dol Guldur in the hands of his servants and slaves to defend.
So, in a way, the White Council was deceived for their plans of overthrowing Sauron failed, they only delayed Sauron's plans.

Why? Because they would know that Sauron had another place to be instead of his Dol Guldur fortress. If you are holding a fortress, and if you care for it and you have plans to be in it, then you wont leave it just because 3 wizards and 2 elves approach.

I don't think this is correct at all. The White Council and many other Elves, Dwarves and Men knew about Barad-dur and Mordor already. You forget that a battle was fought their an age ago when the Last Alliance was made.
Maybe Sauron was already planning to go to Barad-dur, he just accelerated his plans to get rid of the White Council for a while and to conceive his plans without being bothered by such thing.
'Just because three wizards and two Elves approach'? You seem to think the White Council is a circus act. They are five people holding an extreme power, and three Elven Rings.

greetings once more,
lathspell