Not worth an answer - sorry.
You failed the basic requirement.
blkhawk...Many (most?) people on here filed themselves with help from the forum. If you read back in the history there are many useful posts that answer most questions. An attorney is generally only needed if you have a complex case. Look at the N400 application form and count up how many of the qualifying questions you might have issues with.
blkhawk,
The naturalizaiton process is really straightforward if you have a simple case. i.e., you don't have any criminal history, arrests, DUI/DWIs, complied with your immigration status at all times, didn't vote or register to vote, wasn't a member of a terrorist organization, filed your taxes throughout the last five years, and didn't commit any act of moral turpitude (see the last part of your N-400 for those questions), and you met the physical presence test to see if you're eligible for naturalization, with no trip exceeding 6 months (cause of abandoning residence), you're case is relatively simple and like the majority of other filers on this forum.
If your case is simple (no issue that complicates it), I would do it by yourself. It's certainly simpler and saves you a huge wad of cash. If you have issues that might raise red flags at USCIS, then it might be prudent to seek the advice of a lawyer.
Ignore the other rude responders here... After all, we're all here because we need help.
In my opinion, the main benefit of an attorney for an N-400 case, is telling you when you can save money (and sometimes even your GC) by NOT filing. What I mean by that, is:
- the process is simple enough that anyone can file themselves
- the attorney cannot answer questions on your behalf during the interview
- sometimes your case may require legal scrutiny before you alert USCIS to a past misdeed that could impact future freedom (e.g. conviction, long absence, accidental registering to vote, etc, etc).
Generally, there is little benefit from spending the extra $$$. Sometimes however, the advice might just be worth the expense.
There will be no need for an additional 90 day residency period prior to filing N-400, because you officially remain a resident in the same State where you were domiciled prior to going overseas.
The N-470 is your trump card. Make sure to submit a copy of that and your I-131 when you mail your application, and then take extra ones with you during interview.
If everything is clear as far as your background is concerned, do it yourself man... it only takes couple of hours to do so.
1+2. Unclear. I've never seen anything official covering this one way or the other. I think there is a general expectation that you'll be in the US when you file, but I don't see why it would be mandatory in your situation.
3. FP usually takes place around 6-8 weeks after filing, Sometimes sooner, and sometimes later, depending on service center workload and how long it takes to get your case entered in their system.
4. Impossible to say with any certainty. Probably your best bet would be to consult your DO's tracker thread when you get closer to filing the N-400. Discounting people who get stuck in namecheck, interviews seem to generally be conducted in the 5-9 month timeframe.
I hope that won't piss off the interviewer though.