APPLICATN GREEN CARD THRU MARRIAGE, HERE ON VISITING VISA

[onyeekwo@gmail.com]

Greetings all, I am writing as I need some advice. I am in the usa on a b2 visiting, (from the UK, but i am Nigerian) and i came in because i want to get married to my american girlfriend of 2 years. I would prefer to live in the US as opposed to the UK. I've been here 2 months, we r getting married in 2 weeks and will start the green card paperwork soon after. A few questions -

FOR GREEN CARD APPLICATION -

1.) Does state where marriage is peformed have to be same state we apply for card?

2.) Must we apply to the state where we live? Is there any state were it would be better to apply to, where their laws are more lenient or does it not matter?

3.) What happens if my visiting visa runs out while we are waiting for immigration papers to be processed???

4.) I am currently living with a friend and she with her mum, we will get our own place in a month or 2. For now which address should we put on the forms, and does it matter?

5.) Will using a lawyer give us an advantage?

6.) How long b4 we get called for an interview?

7.)She has 2 kids .... will this cause any problems for us (make the marriage not look authentic) and if so do we have to inform uscis a the kids?

Pls I know this is a lot but any advice on these matters and other tips would be highly appreciated. Thank you so much.