With that said, is there any "gold standard" for STNL?

Marcus and I have not touched base in a while (we should do that), and I'm not going to pretend like I know everything about him, but I know he does more than just serving as an agent and is always expanding his own business so, maybe he could be of some help to you.I like many things about Marcus, and not only that he's a pretty snappy dresser (for Wisconsin standards anyways - lol).

Then, assuming you have a contractual arrangement with your buyer, just represent him/her as fiduciary and the seller as Customer, in a normal brokerage transaction.The other option is to just put the property under contract, then assign the contract, but again, this needs to be fully discussed in advance with her broker, then fully disclosed to the seller, so they can't come back later and sue you for making "too much" on your transaction fee.I strongly suspect that your sister will be required by her broker to use standard contracts and forms made available by your state's real estate commission. 

@Ronald Rohde part of my question was if they can give me a 2 day notice to increase rent or just plain ask me to leave, or rather if there is a standard 30 day.

Ask the standard questions: age of the home, size of the home and lot, number of beds, baths, is there a garage (attached or detached), any recent renos (were they inspected or permitted), how much of the space is finished, etc.

The reason is I know which lenders: do a good jobstay on top of the necessary tasksknow how to be creative within the rules (some people don't fit into the standard mold of a buyer, and some lenders don't know how to get them approved, and some lenders know how to get them approved)and which lenders can actually close deals.

heating oil tanks are NOT regulated by EPA. you have to look at your state cleanup standards. 20,000 ppm is significant but the good news is that heating oil tends to be very viscous (unless you were using no. 2 oil) so it may not migrate very far. the cost dramatically increases if you have groundwater contamination and the groundwater is used for drinking water. you need to engage a environmental consultant, not a tank contractor.

Although @Guifre Mora presented some common situations there are a number of lenders for which 12 months is standard and extensions can go several months without penalties and there are no prepayment penalties so it really depends on what matters most to you. 

They already made it clear they don't want your input or opinion.... you are just there to do the paperwork for them....When it doesn't sell due to be being overpriced, they will blame you..... they will reject offers and it will be like pulling teeth to get them to lower the price and they will be pissed if you convince them to do itKind of stalking you on social media etc..... pretty standard nowadays.

All else aside, given the amount of rent you could be charging it may be an idea to sit down and develop a long-term (2-4 year) budgetary plan for the unit/complex so that you can 1)gradually increase rents to a more uniform standard--as one member stated, "if they are all comparable units, there shouldn't be a drastic difference in the rent amounts" 2)eventually get all the units with equivalent or comparable upgrades (to keep things even with the neighborhood comps based on ammenities), and 3)ease your mind about the financial plan and trajectory of your complex (so you can just follow a predetermined plan and adjust when needed as time progresses).