1) I can identify with you in the sense that it isn't love that bonds me to them as my family, but a great respect for who my parents and my own sister are and how they act. If they betrayed me somehow, I know that they would lose my respect and hence, my "love"
2) In my mind, love (non-platonic/eros) is not a serious matter. I'm 17 and have had a few serious (to me) relationships. I find that when I meet a pretty girl, I know right away whether or not I could fall in love with that girl. (Platonically/philia) I believe that love constitutes the commitment of your emotions towards a person, that you can feel safe sharing your thoughts, feeling and actions with the person. Family doesn't automatically make someone guaranteed to receive love, it is earned, like respect.
3) I really don't know how to help you there, I just know my opinions of platonic and non-platonic love.
P.S. I'm a rather strange ISTP (I feel like) when it comes to my opinions on this subject.