Retirement tax questions

I appreciate your response but I'm really looking for answers from either an Expert or a Champ, or gallery opinions that cite a link to answers on ssa.gov.

 

I hope this Ask The Expert event isn't going to devolve into a social media thread. I fear that Experts or Champs will bypass posted questions if they see that there have been responses. 

 

For anyone else reading my questions -

1. I found the answer. Four months.

https://www.ssa.gov/benefits/retirement/apply.html#:~:text=Apply%20four%20months%20before%20you,age%....

 

2. I found the answer. It depends on when you were born. I was born in 1952 so, for me, it's age 70.

https://www.ssa.gov/benefits/retirement/planner/1943.html

 

3. & 4. I haven't found answers and I'm particularly interested in knowing the pros/cons of delaying collecting after age 70.