COS abandoned/ denial due to travel . Do i need to worry/take any action ?

You should have no worries if the visa was approved.

What should I do if I need to leave US for about a year while my I-485 is pending?

You need to speak with your lawyer, but most likely, you will have to apply for a visa overseas.

Am I in trouble? What is the solution?

I am bit confused. You need to consult with an attorney: generally, one cannot work in the US without an authorization. The consequences should be...

Who can help me?

You can look for a lawyer using this website or by calling local bar associations.

Can I keep my last name and change it when he comes. Or should I change my name for embassy purpose

You do not have to change your last name, but if you chose his last name at the time of marriage, you have to use that new last name.

I apply for Daca they ask for more evidence witch I don't have but got married to US citizen?

You should speak with an attorney: DACA might be helpful if you entered the country illegally.

1) Will the CBP officer at POE allow me to change the status to H4? 2) Will they issue me a new I-94?

I think you should speak with your lawyer about your plans.

It depends on the facts of his case. Consult with an attorney.

1. Do i write the USCIS # given on his EAD card as A Number on the various 2. I 864 what to write 'in Care of Name' Part 2 (2a)

USCIS number and A number are the same things.

Affidavit of support.. using the intending immigrant income?

Read instructions to I-864 form, you should consider fiding a joint sponsor.