I'm thinking if you plant "both" feet on an obstacle, it would be more of a "bomb drop" or "acide drop" type, but not boneless. I mean there are so many names for so-called "boneless", such as if you grab front-side and plant your back foot is doing a "fast plant". I think "boneless" are more of a flat-ground where you plant your front foot to do variations such as a regular boneless, 180 boneless, 360 boneless, 540 boneless, and so on. This can be done don baniks, quater pipes, half pipes, and other ramps or obstacles.
So doing both feet on the ground is more of an "drop" than a boneless. I could be wrong. But it doesn't matter what the name of the trick is as long as you have fun doing them and just skateboard. It's only my opinion thought.
It's like Bruce Lee whould tell his student that the color of belts don't mean anything to him. The belt is only to hold his the pants up and such. So getting back to the skateboarding part of the "boneless with both feet...", the name is just something for people to argued about that don't really appreciates skateboarding. So just do your thing and have fun.
So name the trick whatever you want. It's all skateboarding and all having fun. Enjoy.