Re: Life around Proxima?
Usually Centauri A is put forward in both science and science fiction as a candidate for life, since it is much more like the Sun.
My concern about being that close to a star, even a dim one, is that very small changes in the star (like, as you say, flares) could have a huge effect on the planet.
I think the jury is still out over whether planets can form easily in a multiple star system (have any extrasolar planets been detected in such systems?), although it has been established that if planets did exist, there are stable zones around these stars where they could maintain orbits.