1. YOu can refer our support forums to check currently what version is running or you can also check the themeforest page of the theme .
You can also check for the updates from the wp-admin dashboard ->updates ->check again .
2. refer : https://wplms.io/support/forums/topic/auto-updating/
https://wplms.io/support/knowledge-base/manually-updating-wplms/
3. No it is should be your envato username and the api key .
You can find the api key
On the top of the page move your mouse over your username and you’ll see user menu there.