I just finished writing to my host asking them to check rewrite situations since i had an all white-blanked out site even though my db was intact. i had the all-of-the-above list of problems that others seemed to have only 1 part of the problem. dam. i asked my host what could have changed? ask phpmyadmin.
go in to phpmyadmin, and look at the options table. theres a record for recently edited files. the most recent file is at the bottom of the list. my last file i screwed up was functions.php under my theme directory.
this is where the lesson of a backup hits me. i scrolled down, found the copy of functions.php i had made before i started breaking things. i restored my backup file and i was good to go.
i am sorry i do not know what it was that i did to functions.php, but lately it has been all about css. so other folks i saw mentioning theme editing and then walla, a vast whiteness- check myadmin for the most recent file you screwed up and hope you have the backup.
if not, at least you narrowed it down to the file.
