MAL(Mangole Island, Maluku Islands, Indonesia) ?

Anyway, some threads discussed your question 1). An answer is basically YES you can practically terminate your journey on the way, but of course, no refund.

2). An oneworld explorer rule sheet in http://www.oneworld.com/ clearly states child/infant discount.
Infant without a seat - charge 10 percent of fare.
(NOTE If an infant reaches two years of age after travel has commenced but before travel is complete, a full child fare ticket must be purchased for the entire journey. Exception, For sales in Russia, for travel commencing in Russia: Infat under 2 without a seat not permitted.)