Do not pay $1400. For neglected animals you know nothing about, or take on the responsibility for caring for these animals before you know if they're capable of being useful.
I would either take them as is where is and then do as wild_spot suggested, or insist that the owner get them trimmed and in some sort of shape to show you as a purchase.
I'm assuming that the 3 yo walker is unbroken? I just want to point out that by the time you get him gelded, rehabiliated and trained, you'll have a lot of money and time in him, enough money to buy a nice, well broken pleasure horse that will be rideable on day one.
It must be very hard to drive by neglected horses everyday, and I understand that you want to do something to help these animals out but there is huge potential here for you to get into more trouble than you know how to get out of.