. - In the unlikely event that you get a lead, A "motivated seller" who will work with an 18 year old to sell their home, is likely someone dealing with death, disease, divorce, or disaster.

Subject-To is for giving someone who would not normally have control over the loan control over it.

Of course unless your buying defaulted notes at the get go then again as Chris mentioned this type of fee should be handled up front.. and if it new origination your making and then they go bad.. in your foreclosures you can charge the borrower these fee's when they cure or add it to you opening bid and when someone buys it at the court house you get repaid..

If you are looking for proper guidance from someone that has house hacked quite a few times and has the knowledge and experience to help get you going in the right direction, I recommend reaching out to @Josh Green.

He believes he can find all that he needs to know on the internet.

Just because someone is buying at 70 to 90% of value doesn't mean anything with respect to the 1% "rule".

In markets like that or even beachfront property there will always be someone to buy or rent it.  

Quote from @Zachary Deal: Choose neutral safe tones and get nice materials but don't splurge too much on very fancy cabinets, counters, appliances that someone else may not value the same as you.This is so true.

Can someone walk me through the thought process I should be using when constructing the offer?

It sounds like you sold, but if we can ever help with anything in the future please don't hesitate to reach out, even if I can't help someone in my network probably can.