Hi Rahul,
Apologies for the delayed reply.

1. Your server seems to send invalid json response. It can be caused by any other plugin/theme code. Please check console after clicking on submit button and you will see server response. Check for the message it shows. That will give you the idea.
2. Add the field to “Base” or the first Profile field group in User->Profile Fields screen and that will be picked.
3. Are you using any plugin for terms and conditions. It is not part of default BuddyPress. Please check and disable the plugin and It will be gone.

Hope that helps.

Regards
Brajesh