You could just ask if the scholarships are still available, since they are otherwise automatic-for-stats.
For FAFSA, after 10, you can submit another one later with the remaining schools.
In terms of deciding which (if any) of the three to apply to, obviously your first criterion is whether the scholarships are still available. Then, it depends on what your other criteria are. You may want to check the course offerings of your possible engineering majors to see which schools offer more in-major electives and subareas, or which subareas.