I don't think cabinets and such are part of the slide out integrity, although they do make the slide out stronger. But the slides are usually built and then the cabinets and such are installed, and then they are put into the camper.
We did a Denali Factory tour a few years ago. Here's a couple photos I had of the slides. Maybe this will help in your planning.
Here's a photo of my own camper (Outback) after removing all the stand alone furniture. I still think the cabinets may add some integrity, but it's still originally assembled to the completely self sufficient.