On The Inlet Of The VZ SV6 Manifold, There Is A Hose Attached To The Front Left Pipe On The Manifold. What Is This Hose Actually For? If It’s Cracked Does It Matter?

That's part of the crank case ventilation. The problem with it being cracked is not so much due to the crankcase ventilation, but the fact that it will cause a vacuum leak in the manifold. This results in a poor idle quality and possibly decreased throttle response.