Why do these disappear? useless if they disappear.

Why do these disappear?

My first reaction to Ng5 was that if black can play h6 and force us back it doesn't seem good. However I considered if there was a N sacrifice Nxf6 but couldn't see this working well. 

However I then spotted after 7.     h6 maybe N-e6 threatening Q forcing P(f7)xN then Q-h5+ g6 Qxg6++ 

if 7 N-g5 f6 the still N-e6 threatening Q and cannot be taken unless unknown rule intervenes. 

What questions do we ask when? I guess none until black makes 7th move then intensively look for black moves that take knight if it moves to e6.

Is this your plan An T? (Nice plan, I wouldn't have spotted this without your suggested move.)

7. Ng5

Kongo should not be invited to this group. Not sure how this works do I have to invite people here or will they find it?