Photo management questions

My advice would be to explore all the available options and not to reflexively lock yourself into a Lightroom solution. I've used Lightroom since its very first beta release in 2006 yet I'll say that it isn't the approrpriate tool for everyone.

Another suggestion is to read the book "The DAM Book: Digital Asset Management for Photographers" by Peter Krogh. He also runs a website where he distills many of the thoughts in the book:

http://www.thedambook.com/

http://dpbestflow.org/

Lots of tools available to help culling and sorting. You can also use an automated solution to file renaming (once you decide on a renaming strategy; several of which are outlined in the book I suggested). My personal favorite is Downloader Pro from Breeze Systems; equally good is ImageIngester (recently replace by Ingestamatic, but still available). Both packages have trial periods which is all you need. You can move all your image files to a temporary holding folder, point either software to the folder, and they will automatically scan the EXIF metadata and rename, move and sort the files into folders based on criteria you establish through "tokens."

http://www.breezesys.com/BreezeBrowser/breezebrowser.htm

http://basepath.com/site/detail-ImageIngester.php

By intentional design Adobe software, including Lightroom, will not write to raw files with the exception of modifying the file creation date. And even then it will not modify all the relevant time fields.

Lots of options here; Adobe Bridge, Adobe Lightroom, Photo Mechanic, Phase One Media Pro are among some of the leading choices. While they all index image files in databases, not all of them require you to first "import" those files into a catalog. So it depends on how you're personally comfortable working.

Lightroom and any other image tagging software will write IPTC metadata and editing instructions/recipe to the file header space of rendered file formats like JPEG, TIFF, PSD, etc. For raw formats Lightroom cannot write IPTC metadata/editing instruction directly to the file; you can instruct it to save the information either to its internal database or generate XMP sidecar files.  This is a critical distinction since if you use your camera manufacturer's software or third party viewers you may not be able to view/interpret the editing instructions.

DNG may not be a solution for transferability since very few programs outside of the Adobe lineup can handle DNGs and they sometimes vary in what they can do. Many software packages will only generate and interpret linear DNGs.