Ask for help after H1B layoff

My position was eliminated a few days ago and this Friday will be my job termination date and last payroll date. Company attorney said that they usually will report the date to USCIS in 1-2 months, and USCIS usually treats H1B as not out of status if new petition is submitted within 30 days of last payroll. My H1B was extended a few months ago and will expire in 2019 as showed from I-94 on I-797. I have approved I-140. My wife is on H4. We have a 2 months old baby born in U.S.

Now my plan is to search for new job and at the same time let my wife applies for F1 from language school (as community colleges already starts their semester) and I apply for F2. I have some questions to ask to our gurus here:

1. Should my wife apply for F1 and I apply for F2 immediately, or wait for a while (say one month) if I can't find a new job by that time?

2. I heard that the class start time for F1 petition has to be earlier than out of status time or else the petition will be denied. Is this true?

3. If I submit H1B transfer (change of employer) petition without submitting F1/F2 change of status petition earlier, should I do premium processing? If not, can I start working for the new company once I get receipt from USCIS? If yes, and if it is approved and I get new I-94 with updated validity time, can I start work immediately? If it is approved without new I-94, should I go back to my home country and apply for new H1B visa (my H1B visa already expired last year)? And what does my wife need to do?

4. If I find a job and submit H1B petition after I submit F1/F2 change of status petition, should I do premium processing (because I don't want F1/F2 result comes earlier than H1B)? If H1B is approved with new I-94 date, should I just withdraw the F1/F2 petition by writing a mail to USCIS? If H1B is approved without new i-94 date, should I go back to my home country and apply for new H1B visa? And what does my wife need to do? If H1B petition is denied, do I (and my wife) have to go back to our home country, or can we stay in U.S. waiting for F1/F2 petition result?

Thanks in advance!