Also, as I already mentioned on the feedback thread, you are also welcome to now submit Custom Wearables without the avatar cut out :D
We will also accept them WITH the avatar cut out for those of you that prefer it this way, and will accept both when submitted as two separate items. We will NOT be allowing you to replace existing BGs without the avatar cut out, but you are more than welcome to submit a new version of an already-existing BG without the cutout!
No, the old backgrounds on site will be staying the same. :)
You don't have to use the beta wardrobe for doing your entire avatar. If you can at least get those backgrounds to show up, you can complete the rest of your HA in the current wardrobe (I believe). I'm not a programmer on the wardrobe, so I don't know why your items aren't showing up. :( Have you filled out a ticket about it or posted somewhere?
Honestly not sure!