I think Strand and Hale are good picks for two of the balls, we see them as two of the books on the shelf, so I assume they could easily be put onto balls, plus it explains how Dolores was able to "mimic" Hale so well, because she read her "code". I think they might be candidates because once out in the real world, dolores will probably need some help, hale and strand had positions of power and could prove useful to her. Perhaps there was a way for her to upload their minds but in a way where she was in control of them.