1.
I carry my Hasselblad in a pack just like many other people. I also carry Voigtlanders, Nikons, Graphics and Graflexes in a pack but not all at the same time.
2.
I use it hand held, just as I use Voightlanders, Nikons, Graphics and Graflexes hand held except for available light night photography.
3.
I do that for EVERY camera. I do my cropping BEFORE I take the photograph. That is considered a good practice. Maybe you like crooked photographs; I do not.
4.
I have never taken photographs of models. Why model pout is beyond me. I never understood it and never could understand why one would want a photograph of a pouting model.
5.
I never had an assistant and would not know what to do with one. I change the backs myself. I can even load film by myself.
6.
It is a neck strap not a shoulder strap, and I have not had a problem with Hasselblads on a neck strap. I have never had a problem with Voightlanders, Nikons, Mamiyas, Contaxs, Canons, Rolleis, Kodak, Fuji, Minolta, Ansco or Argus cameras on neck straps. I do not use a neck strap or should strap for Graphics and Graflexes.