Regarding H1B | Seeking urgent guidance (In Status/ Out-of-status)

Hi Team,

Scenario:
I came to the USA on H4 visa(dependent visa) in April, 2018. Then, my potential employer filed my H1B visa in April, 2020 and it got approved on Sep 15, 2020. My H1B visa was filed with COS(Change Of Status).

Beginning Oct 1,2020, I am on H1B Visa. But I received an offer letter from my employer to join on Oct. 16, 2020.

Question:
(1) Will I be considered as out of status from Oct 1- Oct 15, 2020 since I haven’t started working?
(2) My employer must have to generate pay stubs starting from Oct. 1 to maintain my H1B status?
(3) This 15 days can be considered in a 60 days grace period?