Mi Hermana pointed out a helpful page in the Lonely Planet South Pacific Phrasebook, which helped to explain the differences in Samoan "T-style"/formal and "K-style"/informal speech, in terms non-linguistics nerds can actually understand.
Yes, we've both apparently been obsessing separately about our nephew's name. Nuestra Otra Hermana didn't grow up with a name her peers couldn't pronounce. We did, and understand how current mainstream American values will perceive Tanielu/Tani/Kangi/Kangielu/Kanielu/Tsanielu/Tsangielu.
Wouldn't have it any other way.