I wish i had the same luck. I've gone round and round with Apple support to get an iPhone 6 with swollen battery fixed, and today they told me, they were sorry but the phone is out of warranty and can't be fixed. The battery is available for replacement but after testing at their service center (shipped from Best Buy to Apple and Apple returned unrepaired) they found other problems that would prevent them from just replacing the battery and unfortunately the phone is past warranty and can't be replaced. The Apple support guy (supervisor) even suggested that perhaps the battery might have caused the excess damage that Apple deems not covered.
BTW, the phone worked fine when i took it in for battery replacement other than having a swollen battery. I guess the only thing i can do is put an unauthorized battery in the phone myself and hope it never explodes.
Very disappointed with Apple service. It will certainly influence my purchasing decisions in the future.
Take it to an Apple Store if you haven't already. No matter the condition or warranty, they will replace the device for the battery price of $29. I didnt read the whole thread, are you in the states?