Having recently enjoyed the company of delightfully gracious and astoundingly easy to please young guests, I say decorate any way you like for yourself, and just keep having teenagers over. I can only very vaguely remember being so young, that basic physical comfort didn't take extensive thought and planning.
Very personally, I prefer more solid, actual-midcentury versions of that particular Ikea chair. That's only worth it if you have joy in the hunting and the history and the construction, though. And I tend to have guests too tall for that model. The recent teenage guests (brother and sister) were both about 6 feet!