Antwoord op "How do I upgrade to Android lolipop"Go to settings > about device > system updates > check now. If it doesn't come up then your device probably can not support that version of Android.
Antwoord op "Model SM-G930F which carrier does this model support?"According to this: https://www.frequencycheck.com/carrier-compatibility/ApjPHYG/samsung-sm-g930f-galaxy-s7-lte-a-samsung-hero/h2o-wireless-united-states it should work on most carriers.
Antwoord op "Where do I buy a replacement speaker?"I think something like this is what you are looking for. IPhone 6 plus earpiece http://www.amazon.com/Original-Earpiece-Speaker-Replacement-5-5inches/dp/B01B1KDZWM/ref=sr_1_4?ie=UTF8...-4&keywords=iPhone+6+Plus+replacement+spe...