Laid off and have questions

[zeus2000]

Hi, I have a few questions about H-1B and switching to B1/2 status. I was recently laid off, and have an effective termination date of Apr 27. My firm also told me that they typically notify USCIS of this on May 15th. I am currently looking for a new job, but want to also plan in case I don't find one. Thanks in advance for taking the time to read these questions and help me out with them.

1. If I find a new job before May (or May 15th), can I start working the moment the new employer files a petition? Do we have to wait for any notification from USCIS (like a receipt) first? If not, can I work the same date as the postmark date of the filing?
2. In the above case, does my employer still have to file an LCA with DoL? If so, how long does this process take? I guess what I'm trying to wonder is, if I accept an offer and they begin paperwork on Day 1, what day can I actually work?

3. If I do not find a job, when should I file an I-539 to change status to B1/2 (does it matter if B1 or B2?)? I guess what "postmark" date should I do this by? Apr 27? May 15th?
4. After I mail in the change of status, but haven't actually changed yet (I hear this can take 2 months?), and I get a job offer, when can I start working? Do I lose my "instant-work" ability, and have to wait for the H1-B petition to clear? Is this when I want to use Premium Processing and hopefully be ready in 2 weeks? What happens to my pending B1/2 application?
5. If I already received my B1/2 change of status, and now find a job, when can I work? Is this the same as Question 4?
6. I understand that I am no longer subject to the cap, so my employer simply has to file a LCA and a petition for H1-B, in general?

7. In the I-539 form, it asks to mail in my I-94 card (original). Until I get a new one, what status am I in? If I end up leaving the country then, what card do I surrender? It feels weird to not have a I-94 on my passport...
8. The I-539 form seems simple enough to fill out. Any thoughts on whether I need a lawyer for this?
9. Did I forget anything?

Thanks so much again. I look forward to your helpful replies.

[zeus2000]

I haven't received any responses yet, and could still use help on the matter. Please, I want to hear your thoughts!