Correct, I copied index.php, not moved it, which is why I have 2 (sorry, I used the wrong word there).
Yes, the header path was changed correctly before, to include the /wp dir.
No, I don’t believe I copied any .htaccess file because I didn’t have one in /wp. I did have an old .htaccess file in root for my previous blog setup, but I think I had backed that up and deleted it, and let WP generate a new one. I don’t remember that step entirely, but regardless, there IS an .htaccess file in root now, and it just reads:
# BEGIN WordPress
# END WordPress
Should there be more code in that file?
Yeah, the answer is not there. I’ve reviewed that a few times, but no dice.