Sorry, I had to attend to some affairs and respond only now.
So, turns out the guard that patrols the wine cellar indeed is triggered by the slightest sound from the upper floor, and it is no surprise. In fact, the player can see this guard without the cat sight ability due to the fact his torch emits the smoke that goes through the second room's floor and can be seen quite well. It looks very funny, so I had my laugh.
I had also tested the weight system and, yes, I see very subtle changes in the model. Beams seem to withstand the player who has eaten and digested three guards, so it is alright for the current version of the game.
While testing it I have found out a very overfed (through debugging P button) player can make the entire map very anxious and bothered by the loud sounds of gargantuan gut that cover the entire map and trigger even those three guards at the very bottom of the map in the wine cellar.