However, this price is much lower than the listing, and the seller is unlikely to accept it.

You never know who will apply, and you are not obligated to accept them.

I just accepted your friend request and followed you bac 🙂

While I never before or since accepted any like offer, the amount I was paid for minimal time was too good to pass up.

Credit score is acceptable, he has no evictions, have enough income to cover rent comfortable. but then i am here as it's useful to learn from others experience for this kind of profile and background that I have no experience with.   

I would like to have a loan calculator in order to do offers with out using mortgage broker before have accepted offer.

A concession is primarily for the buyer(s) benefit, it can help seller(s) to sell a property but there is really no advantage to a seller accepting an offer with a concession except that it is incentive for the buyer(s) to focus on that property, it makes the terms more attractive. 

After much back and forth with our attorney and their regulators, etc they decided series LLC’s should be a part of their customer base and have rewritten their policies to accept them (and us).

You can use a  hypothetical  purchase price and loan amount for the pre approval process  as this will get revised to the actual figures once you have located a  proeprty and have an offer accepted

Bottom line - All hype, bs, misinterpretation, opinion bias, etc aside, sellers willing “owner finance” the sale of their property for one reason - and one reason only: They PERCEIVE that they are getting a higher price for their property by owner financing than by a cash (cash to them) sale.The “perceive” part is why buyers can sometimes structure terms ridiculously one sided in their favor - because some sellers are so focused on PRICE they become oblivious to anything else.It’s why I and numerous others have been able to structure 20 year owner financing loans at ZERO interest; why sellers have accepted “substitution of collateral” that gave them a lien on recreational land I had rather than their own income producing property; why sellers accept second position liens and allow buyers to obtain new first mortgages ahead of theirs (subordination), and why sellers always accept mortgages without my personal guarantee.I myself sell properties and provide owner financing to obtain a higher price.