2 sn Unclean spirits refers to evil spirits.
3 tn Literally a relative pronoun, “who.” In English, however, a relative clause (“bringing the sick and those troubled by unclean spirits, who were all being healed”) could be understood to refer only to the second group (meaning only those troubled by unclean spirits were being healed) or even that the unclean spirits were being healed. To avoid this ambiguity the pronoun “they” was used to begin a new English sentence.
4 sn They were all being healed. Note how the healings that the apostles provided were comprehensive in their consistency.