There's a possibility that I'm missing relevant game mechanics information here but:
If we are to accept and proceed with the information Halsey is providing here to proceed with a lynch, we have to assume that both the messenger who sent the information as well as Halsey are town and acting in the best interests of town.
Let's assume the messenger is operating in good faith then (i) The messenger is a townie, (ii) said townie despite already having a main ability (messenger) also somehow has important investigative information about who mafia is (iii) If the information is received through investigation, either by him or through an associate, he would have received the information only after the night is over and would have to send the message next night. However, the fact that he sent the message with the information as his night action itself, means that, he had that information by default without using any night action i.e. in his write-up (not accounting for mafia qt as we are assuming good faith) (iv) said townie has reason to believe Halsey is townie.
Therefore if you believe this is good faith townie information, you have to assume the messenger has important information on the identity of mafia by default while neither using their night action nor anyone else using their night action (even assuming a town mini-QT). This sounds extraordinarily unlikely to me.
The far likelier outcome is mafia/prankster who knows exactly who mafia/town are and sending a mixed message to confuse town and control the frame of discussion from early on.
In addition, there's a very obvious Olympian (maf) candidate who was one of the 12 olympians and the messenger of the gods who was also known as a 'divine trickster'. Hmm.
In myth, Hermes functioned as the emissary and messenger of the gods,[6] and was often presented as the son of Zeus and Maia, the Pleiad. Just as well, he is regarded as "the divine trickster,"[7] for which Homer offers the most popular account in his Hymn to Hermes.[8]
In the above light, how is Halsey 100% sure of the source of this extremely suspect message? If Halsey was town and received this information, would he wait for a round or two to get more info on np and Daemon, maybe press for more information without revealing all his cards instead of just doing this? It seems quite unnatural tbh.