RASD

I inherited an overfunded one-participant plan. The participant is the 70 year old owner with three year average pay of $100,000. Maximum 415 lump sum is about $1,000,000, but plan has $1,560,000. She could take the lump sum and move the rest to a qualified replacement plan, but the company won't have income going forward (no way to use up the excess) and she wants to close it down (can't have a plan with no sponsor). So I have three questions:

1. If she were to use a Retroactive Annuity Starting Date of her 65th birthday, the back payments with interest would be $560,000. This amount would not be rolled over. Then she could use the $1,000,000 to purchase a life annuity with payments of $100,000 per year. Is this correct? 

2. If she first took her RASD payments, could she then take her lump sum of $1,000,000? Or is this a 415 violation?

3. What if she were 71 (70-1/2 in 2019) and already took her RMD for 2019 and 2020. Does this affect the answers to 1 & 2?