Hi Daniel,
I think you need to elaborate a bit more on your property feature class/layer that you created. You are saying there are no fields populated? Are there fields created within the feature class?
I have a feeling you are going to have a lot of work ahead of you to join your spreadsheet data to your newly created feature class especially without having any attribute information for your properties. Ideally, when creating a new feature class you need to have a unique identifier included, such as a rollnumber or PIN number for properties. Then using that unique identifier you can JOIN it with another source of data (another feature class or table) based on that unique identifier. If you have another feature class that already has the unique identifier and it intersects your new feature class you can perform a SPATIAL JOIN to transfer the unique identifier and other attributes from one feature class to another.
The key is you need that unique identifier within your new feature class to join with your spreadsheet. You will have to do it manually unless the OBJECTID's in your new feature class match the record ID in your spreadsheet. If so you could probably do an attribute join based on that, but they must match perfectly.
I hope this helps.
Cory
