I received my Velka 7 a few days ago. I didn't bother checking since it'll be a while to get all my parts, but after reading your post i checked. I do have everything, rubber feeting and power switch as well.
The transparent plastic bag (left) is the one that missed in my box. Also, I am experiencing the same issue on 24-pin power connector that not fit with the front panel. I use Asus B550i Strix motherboard.