Your lighting and the choice of backdrop will have as much of an effect on the results, if not more than the choice of film and developer, in my experience. If you are looking for a happier, lighter mood, may I suggest a bright, even a white background and plenty of diffuse light, which will cause a little flare that will soften the look. If you want to use a 400 film, I have some experience of Tri-X in XTol for that look. For a sombre, grittier look, go with a black background and less diffuse light, or fewer light sources. Marry that with HP5+ in XTol or Tri-X in Rodinal and the portrait will have "character" but maybe not what a family one was calling for. Having said that, HP5+ in XTol, with a lighter backdrop, and a light yellow filter, #8, will give a neutral, pleasing look. FP4 is a good film too, but you asked for a 400.
There are many other combinations which others will no doubt prefer, these are the only ones that I have any reasonable experience of.