Facebook – In Facebook, is it possible to delete multiple friends

To remove a friend:

1. Click "Account" on the upper-right part of the screen
2. Click "Edit Friends" (first option under your profile picture)
3. On the left sidebar, under the "Lists" section, click "Friends".
4. Find the friend(s) you want to remove (you may need to click the arrows at the top or bottom of the list) and click the "X" button on the right.
5. A message will pop up asking if you really want to remove them. Click "Remove".

If you want to block someone, so they can't contact you at all:

1. Click "Privacy Settings" under the "Account" button on the upper-right part of the screen
2. Under the "Block Lists" section at the bottom of the page, click "Edit your lists".
3. Type the name or email address of the person you want to block, and click the corresponding "Block This User" button.
4. If you want to unblock them later, follow the same steps, but click the "(remove)" link next to their name/email address in the list.

My understanding of the "Hide this post" functionality is that it will hide that post and all future comments, like etc on that particular post.

If another friend posted the same picture again you would have to hide that post too. Facebook isn't intelligent enough to recognise, what are essentially, duplicate posts.