Reporting in another two data points to show that awards with partners might not be subject to married segment logic.
I booked flights back in the Spring (so before the most recent changes) for AUS-SYD and return on separate tickets for early 2016 travel. There was not low availability out of SAT at the time. Today I was searching and found SAT-LAX and LAX-SAT in R class (lowest first class). I called and got transfered to the reissues desk where the agent was able to change both of my AUS-LAX and v.v. flights to SAT. She mentioned having to confirm the miles required wouldn't change, and the TPAC flights no longer have availability. There was no extra charge in miles, and I actually received a refund in taxes/fees which I think is due to the relative value of USD to AUD now compared to when I booked (airport fees being unchanged in AUD but now less in USD).