Preforclosure contract assignment? Am i correct?

Ok let me see if i fully understand this, you find someone who’s about to go into forclosure who has a house with a good amount of equity(because the more equity a house has the less is owed on in which means you can get the house cheaper correct?), make a offer(which would be the amount owed + the amount the sell wants to move to their new location correct?) Was all the statements above true? Heres a better example:

I found a house worth - $80,000 no repairs needed.
                         It has - $60,000 in equity
         The seller wants - $4500 so he put toward a new house
    I get the house for - $15,500
      I sell it to a REI for - $25,500
                       I get a - $10,000 assignment fee 

Was all this info correct? Thanks guys for the help.

If it’s worth $80k, why only sell for $25k? If its worth 80k you should be able to get a lot more than 25k out of it.

That was just a made up deal example,i wanted to make sure i had the steps correct.