1.You can choose whether to include Sales Orders and/or Forecasts in MRP at run time.
 
2. If you run MR-C Reset Forecast, Sales Orders and Shipments will consume the forecast amount.  Work Orders Do not consume the forecast, they satisfy it.
 
3. Not sure what you mean but both Start and Finish Dates are generated for Work Orders.
 
4. I think once you get the whole concept, things will fall into place.  If you can't afford to be out of a Finished Good, you need to pad the Forecast, have extra Components on-hand early and just Delay or Expedite Finished Good production to suit sales.
 
It sounds like you need to set a minimum on-hand level for the finished good and then plan not to fall below it.

Safety stock covers problems with planning.  Safety stock is waste, it is expensive.  
 
With added experience and advice, things will go smoother.   If you must have safety stock, start small and set a goal to make it smaller.  
 
MFG-MR-G   Print Material Requirements will show you a running total of your future inventory.  IT shows your expected transactions.
 
If the order action report says to delay an order, then you have enough in the pipeline to cover demand.
 
Forecast and sales orders ( if included in MRP generation) will cause planned work orders to be created for days where there is product shortage [negative on hand quantity].  Material requirements are checked for the parts needed to fill all current and planned work orders.
 
You may also find you have good plans tipped over by damaged parts, manufacturing errors, and poor inventory control.