first time abroad - need some help (Lagos)

Hello all.

I'm not an expat yet, but i would like to work outside of my country.
Now i'm working in Moscow as Facility project coordinator in company who own shopping centers in Russia, but i also have a 3 years experiance in constuction.

I was offered a job in Nigeria in Cappa&d'Alberto on one of their construction projects in Lagos, 16 stories office tower, from the guy who was working in IKEA also, but i have not communicated detailes yet. The position is the project manager's back up on site, speaking on behalf of company to the client, following up a schedule of the project, contractors, construction dairy and so on.

I have never worked abroad and i guess Nigeria is not an easy country to start. SO

1) does any one now this company, cause it is not a lot of info in internet about it. I was told that it is one of three biggest construction companies in Nigeria and that they have more than 20 sites.

2) can you please advise how usually the expat contract does look like. I was told that the project is four years. Does it mean that i will have to sign a four years contract without a possiblity to quit if it turns really hard for me.
which benefits should i communicate exept house,car, utilities, home flight, health care. i gues i have to do some vaccinations?

3) also if possible advise the place of living in Lagos to be on a safety side.
I'm reading different expat forums now and it seems to be quite dangerous country in general.

4) what about the salary, is it better to recieve it on local bank account or on offshore or split.
If it is possible could you also advise an approximate salary level.

5) I also have a wife and i have a possibility to take her with me.
She is an it developer in Deutch Bank. will it be possible to her to find a job there.
and how is life for young white girl over there can it be a problem for her.

Thanks a lot to anyone who'll reply.