I would also require to be a certificate holder, this will notify you should the policy ever lapse or terminate for any reason.

Joe, if you are successful at the sheriff's sale, you will be issued a sheriff's certificate of sale.

You will get a Flood Certificate which will show if your property is within a flood zone.  

You need to be listed on their policy as both an additional insured as well as a certificate holder.

For 3+ families it'd also be good to make sure they have a current green card (issued by the state of New Jersey sort of like a certificate of occupancy renewed every 5 years indicating that the building passes whatever requirements the state imposes). 3 story buildings with 3 units need to have a fire escape, exit signs, self-closing doors, etc.

You obviously can write up a quitclaim deed, but then you personally have to call the bank and pay them off record the redemption certificate.

In addition I signed an "Office Exclusive Certification" to Multiple Listing Service of Long Island directing that the property not be published in the Multiple Listing Service This document specifies the exclusive listing runs from 4/26/2016 to expiration date which was left blank. 

Now i'm trying to negotiate with Ditech to pay them less for the redemption certificate that they bought at sheriff's sale.Has anybody tried doing it before?

Have them fill out a W-9 form, always pay with a check, and if total payments paid to them during the year are $600* or more, then filing a 1099 is appropriate.Also, you should get them to add you as an additional insured (or at least a certificate holder) and have their agent send a copy of their insurance to you directly.  

Concerning average number per state, what are the top states for buying tax lien certificates?