Did Adam Dream?

According to Aquinas, yes.

In his Disputed Questions on Truth 18.6, Aquinas raises the question, “Could Adam in the state of innocence be mistaken or deceived?” (See his parallel article in ST I.94.4). One of the objections he raises concerns Adam’s ability to dream:

Obj. 14. In the state of innocence man would have slept, and likewise would have dreamed, as Boethius says. But every man is deceived in dreams, since to some extent he considers the likenesses of things as if they were the things themselves. Therefore, in the state of innocence Adam could be deceived.

Aquinas answers:

Reply 14. Some say that in the state of innocence Adam did not dream. But this is not necessary, for the vision of dreams is not in the intellective, but in the sensitive, part. Hence, the deception would not have been in the understanding, which does not have free exercise in sleep, but in the sensitive part.

Adam could not be deceived in his intellect, but this is not to say that things could not appear otherwise than they are in the senses. And this is where the “deceptions” of dreams take place.