Funny, a couple of years ago I did a SuiteCRM installation precisely for schools 
I made everything a Contact, I just added a custom many-to-many Relationship between contacts. The relationship itself has a property called “type of relationship” that specifies if it’s a mother, a father, a tutoring teacher, etc.
A “Contact” is a full-rights person in your database, one you want to keep a relationship with. A Lead is just someone “approaching” your organization. You either end up convert him into a Contact, or you discard him.
I had photos of everyone, and nice “Photo fields” in List views, which were very nice to navigate classes seeing each pupil’s face and name.