ad 1) As far as I know, you can access her hidden cellar only when she's dead or when you are undiscovered either by her or her servant.
Just use the torch right beside the immovable cupboard.
ad 2) I haven't found the armory yet, or I found it and it just didn't strike me as "armoryry" enough.
ad 3) the bloodied metal grate just serves as a hint. Just smash the gate and you gain access to the Knight's Tomb, a Titan-guarded dungeon. To access the main are of the dungeon (and not die a swift death), you need a book called "Titan Dictionary", which allows you to converse with either the big titan head in the Phantom Forest or the Guardian of the tomb.
Where exactly the Dictionary is found I don't remember, probably in town. Sorry.
