I will probably get the Passport first since the N600 fee is too much for me currently. I would eventually hire a lawyer or preparer for this matter, but also want to educate myself as much as possible after I went through a hard time and an unnecessary burden getting the I-485 approved. After all, the lawyer I hired made some mistakes that cost me 2 RFE that later I learned could have been avoided and my process would have finished earlier, per USCIS agent's comments. There is less information on N600 filing on the web, and since I live in a small border village in the US, I have to cross to Mexico daily to get basic items, that alone adds confusion on how to fill this kind of form. We don't even have USPS home delivery, so we rely on PO Boxes in a single postal office. Getting proof of address is an ordeal here.
I'm aware that each case is different, but I do believe my case is uncommon because of my residency. I have had uncommon procedures almost all the way. For starters, got the I-485 approved when I was still abroad on Advanced Parol, and there was no clear information on how I had to re enter the US, because would derive citizenship automatically for complying INA 320, but since I was not physically present in the US at that moment, technically I would not comply until I enter the US, but do I enter with the AP, as a LPR or declare I am a US citizen by INA 320? My fear on this matter is the CBP registering my entrance in a category that would hinder my derivative citizenship passport or N600 applications. Eventually, I entered with my Green Card, which seemed the most logical option.
Really appreciate the help and info you are giving me.