The electronics look identical except for the badges (nameplates and decals). I would be very surprised if they're different. As far as I know, Esky is a trading company so they're not actually making their own stuff. So it has to be made OEM for them somewhere and probably the same place that E-flite has theirs made.
I don't know if the main shaft is stronger in the HB2. It's a separate gear and shaft where the BCP is one piece. I have them both ways for my DF4 (which is also the same piece used in the HB2 and BCP) and the separate gear isn't always better. The set screw keeps loosening just a little and puts some play in the rotor. And, even though these pieces may be made in the same mold, they could be different plastics. The BCP has much less gear noise than my DF4.
I also think E-flite is protecting their dealers better. I noticed that the prices for online parts are always very close, and so are the prices in my LHS (which are usually quite high). It could be that E-flite requests dealers to agree to a minimum price. This entices your LHS to carry E-flite instead of Esky because they know the online stores won't undercut them on price. If this is true, it's excellent marketing. It also gives the impression of higher quality when you don't see bargain prices for their parts in some stores.