I prefer the shop having its own independent login, always. For the rest, probably, but I think this is due to different products having all there own authorization mechanisms, which would probably not be trivial to hook to one authorization mechanism ( except probably for g+ et al)
But OpenID or similar are still available. This could also be internal only. However tying everything together is work that needs to be done. I’d rather Fairphone’s software developers work on phone software
Never heard of it. It seems to have a differenent scope at first glance. Persona was meant as a single account for each person for the entire web. Hubzilla seems more like a tool for service providers to interconnect parts of their service. It looks promising for the case of Fairphone.