The concept of a friend is really an earthly one. The souls in purgatory are fortunate in that they will at some point be going to Heaven. Given the chance to escape their suffering in purgatory and “start over” on earth, they would not take it, though they do long to “get out,” and get to Heaven.
I would say that those in Heaven love all equally, except for God whom they love above all, followed by our Lady, the Queen of the Universe.