To me their door numbers are meaningful, too. I'm reading that in tarot, 6 (Brandys door) means a stable connection, balance, security, and peace. Reliability, dependability, etc. All the things you get comfortable with in a long term mess. "He was my lover from the start." Also read that 6 could mean that you are "outwardly focused on the detriment of your internal, spiritual life, and that you should focus on your domestic life in a literal way, including your HOME, SPOUSE, or children.
Monicas door, 7... looks like a "magic" number of creativity and individuality. Perfection and evolution are words I saw. Its said to bridge the gap between mundane, and enlightenment.
Nnnn. These are all things we picked up on over the years in stanning the lyrics. That Brandy was "home" the "usual" .... and Monica was the alluring excitement on the side.