Skype For Business to Skype - Add Video to call

I am looking for a way to video call users from Skype for business to the Skype platform or if possible Whatsapp. The scenario is that an external user can call a number from standard Skype on their mobile phone to myself on Skype for business (Desktop) and if needed I can click on the add video option.

Is this possible? Do I literally just create a policy enabling communications with public users or are there interfaces I would need to purchase?