The student does not have to be the airplane owner (experimental amateur-built), does not have to be related to the owner, and doesn't need to have stayed in a Holiday Inn. As long as the owner of the airplane is not renting the plane to the student (getting paid for the use of the plane) there is no issue. If the use of the airplane is free of charge, anyone can receive instruction in that airplane without running afoul of the FAA. That would include primary, transition, commercial, and IFR training if properly equipped.

If an instructor owns an E-AB airplane in which he/she wishes to provide transition training (not primary training) and charge rent for the plan,e then the instructor needs a LODA letter from the FAA to do so.

If the owner of an E-AB airplane wishes to rent his/her E-AB airplane to someone for flight training and is not the instructor who will be providing the training, I do not believe that such an activity is allowed at all.