It would depend on the moment on which the second funnel collapsed. If the dome was already submerged when that happened, then I would say that it most certainly didn't contribute, since the glass of the Grand Staircaise topping would have given in by that moment. Most probably, the collapse of the dome was caused by "the wave" that rushed aft when the bow gave a sudden lurge below.Also, another question: Is it possible that the collapse of the second funnel contributed to the failure of the glass dome? I’d always wondered what the sounds were that the “Titanic: Honor and Glory” team incorporated into this video were:
Could it be the dome crashing in on itself and the stairs ripping apart?