My I-140 was approved, may I still switch my status from H1-B to F1

A possible problem is that you have exhibited immigrant intent. However, you haven't filed an I-485 so they should allow you to, if the I-140 even...

Can an unemployed US citizen petition for a spouse ?

Yes but you probably need a joint sponsor unless you have a large amount of assets. Run your situation by a lawyer.

Do I qualify for GC - second employment preference?

Hi, the 5 years has to be post bachelor's and progressively more responsible. So maybe, maybe not depending on the specific facts of your case. Was...

You would be violating your non-immigrant status.

Does my husband qualify for DACA?

Sounds like he's eligible. He should talk to an attorney.

Where to start so my husband can obtain a green a card?

You would have to file an I-130 and a waiver of the 10 year bar. Hard to say if you would be successful since you're living together abroad....

What are the eligible ways to get a visa or permanent residence?

A treaty investor or treaty trader visa might work. it would get you a non-immigrant visa. You should discuss with an immigration attorney.

What does one do when a manager calls you "big one"?

Ask him to stop perhaps. Is there a reason you feel like it's discrimination rather than being rude?

Second interview with the INS tommorow for adjustment of Status

That is odd and I'd bring an attorney if I could. Second interviews are rarely a good thing in my experience.

Getthing married to an illigal immigrant, will i be able to fix he's status? or be able to get he's residence?

Hi, from the facts you provided you probably won't be able to help him through marriage. He would have to be eligible for 245(i) (a law that...