Doesn't matter what rapids are since its irrelevant to cutting. On a larger machine such as yours its nice to have since it'll get from one side of the bed to the other quicker but other than that its not important.

As for cutting. Its dependant on material, machine rigidity, spindle power, end mill size, depth of cut etc. But very rough ballpark speeds for a typical DIY CNC cutting wood would be 3m-5m/min at 4-6mm DOC. Aluminium is often cut at 0.7-1m/min with 1-2mm DOC. No firm answer though so don't take that as gospel.

Acceleration is really about reducing cutting time with short moves such as 3D/2.5D. Higher it is, the quicker you accelerate after a direction change.