BLDC Regenrative ESC and LiPo
In response to part 3, by "using this configuration" I assume you are talking about the regenerative breaking part of the instructables article (which has no cell balancing)?

When charging more than one LiPo cell in series, it is recommended that you have a balancing circuit of some kind. Without it, after some time, the cells WILL have disproportionate amounts of charge and the batteries will die sooner than expected.