Just an update to the original question; flew with a 50lb lab in the hold LAX-SGN via TPE w EVA Air in March 2017. EVA charges 3 x excess bag for animal that size so extra cost was US$420. Required rabies vacc and health cert from USA. Required transit permit (free) from BAPHIQ in Taiwan; done via email w no problems. Only problem to note was arrival at SGN, upon collecting dog at carousel a Vietnamese Customs employee walked up and asked if we had a permit. We said we're transiting to Cambodia and they said technically need permit, however, they could help... The employee kept repeating this as we kept walking towards the exit, no money exchanged hands and it didn't seem to be the objective but we found ourselves outside with all bags and the dog and no problem...