Do these have new batteries?
Good morning. The batteries are checked and replaced if needed.
The very first thing I’d do after buying any used/refurb Apple phone from anyone other than Apple… go to to an Apple Store and request a full diagnostic.
The diagnostic is very thorough and should expose deficiencies like a worn out battery. Do it prior to the (in this case) 90 day Woot warranty window.
How accurate is the battery health feature in settings? My iPhone 6SE is around 1 year old and has a maximum capacity of 87%
Go to the Apple Store and do the diagnostic. Honestly, I haven’t asked them whether their test is similar.
BTW, I’ve had really good long term durability performance from phone batteries by always topping them off… when I get in the car, when at the desk, etc… vs. running regularly them down.
Does this include the lightning to headphone adapter?
Sorry, it is not included.
Will these work on Cricket Wireless?
Would appreciate any information someone might share Re:
moving an existing/current TracFone to one of these.
Thank you much.
Just received mine today. Cannot be activated. 
Dreaded “No Service” showing in the upper left corner.
For the love of Noodle, CHECK YOU PHONES WITH A KNOWN-GOOD SIM as they come in!!