When we rent to a single occupant we add a clause to have them grant permission for someone they designate to make decisions about their tenancy and belongings if they become unable to. 

Dual agency is permissible and many agents know how to manage it correctly.

Manifesto: The Mad Farmer Liberation Front” from The Country of Marriage, copyright © 1973 by Wendell Berry, reprinted by permission of Harcourt Brace Jovanovich, Inc.

Still, you do not need the children's permission to buy the 1/2 interest held by their stepmother. 

The second part is post receipt of the written, signed, application (that should be worded so as to specifically give you permission to access information) is where you follow up on the info provided on the application.

If you decide to rent it out after 3 months without the lender's permission, then you may be in breach of the mortgage agreement and that could trigger an acceleration clause, meaning that you would have to pay the entire loan amount in a short period of time.  

I would think it would be ok if we got their permission but I am not sure.

Divide the rent by the number of days in the month and charge her per day.By the way, a "holdover" tenant is one that remains after the agreed termination date, without permission.

I also deleted some names, addresses and content to maintain my clients privacy (who has given me permission to use this example for illustrations): __________________Thanks for getting the property information to me quickly.

The property management company asked permission in July for maintenance works after the previous tenant moved out.