Zac made his Indian Ocean leg of the voyage in the late Spring/early Summer. His sister, unfortunately, is making the same trip during the early Winter.
Not the same trip. Zac did it from SE Asia on broad reach with the SE Trades. Juan Sebastián Elcano did that route in the early 16th Century.
Abby was riding the southern Westerlies with the wind astern - much riskier, Western shipping didn't try that until the late 18th Century.