Ask your teacher about the shower accumulation. I even recite the 100 syllable mantra on the toilet, but I don't count that toward anything
Um as for the five Buddha families, it's true--Vajrasattva is often seen as equivalent to or stand-in for Akshobya who is east/blue/water/anger (which is really mirrorlike Wisdom) except strictly speaking, when you are trying to view the five elements or sense objects as the complete mandala, the elements are actually the 5 Dakinis/wisdoms. So, Water is really Vajratopa or Nyema Karmo, the consort.
Ultimately its nondual, they aren't male/female separate entities or something. But it's so magical to think that all the skandhas and matter and energy are actually just the gross display of the 4 Dakinis in space. Whoah!
All this is my really poor explanation and understanding of the lyrical meditations in Magic Dance
by Thinley Norbu Rinpoche. If you can find a copy, it's a magnificent book! So rich.