I think that would be hard to acheive, it is just going to be a long process adding the lost posts back.
As far as a Like function I have got something working on my test board using the new style that I am working on.
There is a like button on each post, when you click "Like" that button disappears & a list of users who have liked that post appear at the bottom of the post, and on your profile it will display how many likes you have given and received
And a list of users with most likes at the bottom of the index page with the other stats.
I have asked Dr Jones to have a look at it & see if it something we can use.