MacBook Battery Replacement - any recommendations?

[Axtremus]

Hmm ... now that I think about it the second time, yeah, I think it should work. Heck, I think I have that TB3/TB2 adapter. I will go try it out later today.

[Axtremus]

Well, I tested the combo chain with Thunderbolt 3 port connected to a "Thunderbolt 3 to Thunderbolt 2 adapter" to a Thunderbolt 2 cable to a Thunderbolt 2 hard drive.

It works fine. With that configuration I copied 25 GB of data onto that Thunderbolt 2 hard drive without incident. It's a spinning hard drive too using power drawn only from the Thunderbolt 3 port.