Trouble with these kinds of questions is you have to be very specific about what is being asked. I'm not much a performance guru, so I'll tackle number 2.
Stated in Question - Constant Attitude.
Consider how Angle of Attack is defined. I don't recall the text book definition, but something close to the following:
The angle between the Relative Air Flow arriving at an aerofoil and the mean chord line of that aerofoil.
So, in the question, has Relative Air flow changed? I would say No, since the attitude of the aircraft is constant.
Has the mean chord line changed? Well, lowering a trailing edge device has the effect of tipping the mean chord line backwards, thus, by definition, increasing the angle of attack.
Lowering a leading edge device has the reverse effect.
That answers the question.
What happens next is that this change in AOA, plus the effect that changing the camber of the wing will change the lift coefficient, combine to change the lift generated by the wing, so the pilot will have to change the attitude or accept a change in flight path. This is what Greaser is talking about, and whilst he is quite correct he is not answering the question.
CPB