Supplier Release Scheduling-MRP/Planned orders Questions

We're in the process of testing the functionality for Supplier Release Scheduling and I've followed the information in the available documentation (637829.1, 651602.1, FAQ's) however, I'm finding I have questions not answered in these documents such as:

Does SRS require that the primary vendor field on the item/branch record remain blank?

What's the difference between the different statuses on the vendor schedule?

What's the difference between planned and committed quantities on the Vendor Schedule?

Is there any plan/ability to add a default calendar for all blanket orders or for all blanket orders to a certain vendor?

Should the vendor schedule get updated with each MRP run or does the schedule have to be in a certain status?