Wow...I never thought of songs like this before. They'll remind me of anime storylines (you know...when you hear a song and think "oh! that would be perfect for so and so character to sing from so and so show.") okay, so i'll give it a try:
Teddy Bear (ayu)- a dear friend
Because you loved me (celine dion): my mom
Because of You (ayu)- my crush
Shinjitsu no Shi (DAI)- another dear friend
Secret Place (Rachael Lampa)- my dad