Which cell balancing method is best to use and implement for low-voltage (48V battery stack) battery management system for E-bike application?
I would advise on going with a passive balancing strategy if you are to doing it yourself. And I would advise on that for four reasons:


It is much easier to adjust the charging rate of your battery since you can close loop regulate the charging current with respect to the temperature of your balancing resistors. You can thus minimize your charge time by being on the edge (with a safety margin) of over-heating. This is assuming your cells are really crap, thus making balancing power dissipation your limiting factor. In my experience I have never reached the point were the heat from balancing was a problem, when working within the manufacturers recommended maximum charging current. Buy good quality cells to begin with.
Many BMS board that exist off the shelves use this balancing strategy, for which the only drawback is from an efficiency standpoint. And even though there is a slight increase in efficiency, you will only notice a difference if your cells get vastly out of balance. Again buy good quality cells to begin with. 
The regulation scheme and mostly the switching aspect of it is dead simple to implement: (from the cell perspective) "Is my voltage higher than the lowest cell in the pack (+- hysteresis) ?  Yes, discharge. No, do nothing.
There exists open-source projects that you can inspire yourself from, that all utilize this balancing scheme, which will make your probability of making something that works much greater : 


https://github.com/Teslafly/OpenBMS 

https://github.com/foxBMS/foxbms

https://github.com/DieBieEngineering/DieBieMS

https://github.com/EnnoidMe/ENNOID-BMS

If capacitor shuttling strategies were vastly better overall, one of thos smart engineer from these 4 projects would have implmented it this way. Also it is most likely cheaper since chinese manufacturers of 48V batteries all use resistive balancing strategies.

Be careful. Keep a bucket of dry sand around. Or something that would prevent burning down your lab in the event of a short-circuited cell(s).