Ref passports, you actually need to get them translated & this is done at the notary office, if you've bought property recently, & still have the same passports, you may already have had this done.
Nufus is just one of the offices in the belidiye building, it deals with the population.
However, as Ian has already said, if you use a guide, they will take you to all the necessary offices, fill in your forms & do some of the legwork where your presence isn't needed. IMHO it was worth every kurus, I used Arzu Kantur at A&A Translations.
To be fair, I haven't heard of anyone having their residency application refused, including people who live on boats in the various local marinas, so wouldn't worry too much on that score.