I would like to add my 2 daughters (both minors) to a property I've owned for 15 years, but is not our home that we live in, in case something happens to me I would like for the house to go directly to them. Is that possible given that they are minors? What are the implications of that if one day I decide to sell it?

You're better off making a will that leaves the property to them rather than adding them to the deed now. By adding them to the deed you may create a gift tax liability. If you add them and choose to sell the property later you will not be able to do so without their signatures.