ahh, I thought you were talking about something else with the first problem. If its not showing up in your list of pages but you still can't use that name, you could use a DB query to remove that post.
in cPanel, go to phpMyAdmin. Find the "SQL" tab.
In the text area, put this code (you'll need to modify it a little, to delete the posts you want).
Code:
DELETE FROM wp_posts WHERE guid = 'topic'
Now if you chose a different prefix than "wp_" when you installed, you might need to replace "wp_posts" with "prefix_posts" where "prefix_" is whatever prefix you used.
also, replace the 'topic' with the slug of whatever page you want to completely delete.
As wpbot would say it "I have completely espounged 'topic' from my memory".
Hopefully that will fix it :D
I'm still not sure about the second one. sorry.