Hi Ethan,
tx = fundrawtransaction(tx, changeAddress: chaddr)['hex']
I really like the way you have used fundrawtransaction with segwitchange address
can you give some links to these discussions?
I would like to read/join

A lot of it happens in the #bitcoin-core-dev channel on IRC, usually during the weekly dev meetings (every Thursday at 19:00 UTC).
Are you sure about this? I've heard comments that this is not by default on 0.15
You still have to use the cli
That is correct. That's why I said "after 0.15.0" and "It will likely be a minor release" (hint: 0.15.0 is not a minor release).
achow, do you have any idea on the timeline of this minor release? If it will take more than two months, I might as well use Ethan's solution (want to urgently reduce tx fee right)