When I'm playing it's giving me objectives like it would a normal person and they're like "Lifetime points! And coins!" And I have no idea what the even heck that is.
Your "Lifetime coins" is the total amount of coins you have collected over the entire time you have been playing the game.
When you first download the game you run two times. You get 100 coins on the first run, and 600 coins on the second run. Your "Lifetime" total of coins would be 700.
The same principle is used for "Lifetime points".
"Lifetime" anything implies whatever of that category has been gained on this account.
NOTE a new account is started when the app is first introduced to the device.