@NCmom14 the answer really is that it depends on your school(s).
If you are attending a school that uses the CSS Profile, then chances are that the FA officer at the school has seen several variations of folks who have used this type of asset as an investment over the years, and they should be able to tell you how they would treat your situation hypothetically if you took different actions.
Be up front with them, you understand that this investment was made in part as a savings vehicle toward your child’s education, and since you were thinking of selling anyway (it is not uncommon for parents to no longer be able to maintain a rental property asset if they no longer have their own kids at home to look after the primary residence), you just want to be sure you are making an informed decision, thinking about all the potential consequences, etc. Be clear that you are not looking to them for investment advice, just potential FA implications related to different possibilities. There often are legit other reasons to unload a rental property - as we get older the stress and upkeep can be harder, losing a tenant can be very stressful, etc. The FA office will usually not immediately think you are trying to unload a property to maximize financial aid. At the same time, if you keep the property and next year you will only have 8-9 months rent instead of 12, plus some remodeling expense, etc., sometimes the school will understand this will make it difficult for you to contribute as much toward the parents EFC.
And of course, whenever you speak to a FA officer at any school, remember to use the occasion to thank them and the school for their assistance in helping your child afford such a great school. Too often folks tend to think of the FA office as adversarial, when in reality, most of the time they are very very helpful and glad to be able to be a partner in the process.