If immigration wasn't an issue would you still be together? I think that's the issue other posters haven't mentioned. Never mind trying to put assemble stuff to appear together. You could try to file with divorce waiver if you feel that is where the relationship is headed.
Don't even try. Comming to the US with a non immigrant visa with the intent to marry is fraud and then adjusting status. Go the spouse visa route. Marry in a 3rd country if you have to
Why do you think you need an attorney? If it's a straight forward case and you can follow instructions on the forms then you can file yourself and save your money.
Please complete your timelines they are blank. Ask your self this, no trips more than 6 months, more than half the time in the U.S. Living together up until naturalization. Good grasp of history, civics and English language