You can send the admin access here simply using a private comment. When you post a reply with your credentials just ticket the box “Set as private reply” and that’ll be all.
Regarding the video background we can’t help you out as it’ll load all over the site & that’s how it’s designed. In that case we’ve to modify the whole system of playbit & adds an extra option field to load video or image on background for homepage only which will cost you as it’ll be under customization task. Only unmuting the video won’t cost you but other thing will for sure.