It is difficult to "translate" a culturally loaded revelatory word like vates, but a gloss such as 'prophet' or 'oracle' (oraculum) or 'seer' works. Soothsayer can have a derogatory sense in English, so I would avoid that for a gloss. Bard is archaic English and so I agree that as a gloss it limps. The base sense of prophet/oracle/seer--one through whom the gods speak-- is present even when someone like Vergil uses it in poetic context. I would avoid "wiseman" as too gender specific; vates were often female, most famously the Pythia at Delphi.
In the Aeneid, the Sibyl--definitely female!--who leads Aeneas into the Underworld is called vātēs : for example, Quae contrā breviter fāta est Amphrȳsia vātēs , in line 6. 398 ("The Amphrysian vātēs spoke these things briefly in return"), and she's a plain vātēs in line 6. 419, when she throws a drugged cake to Cerberus to keep him quiet (Cui vātēs horrēre vidēns iam colla colubrīs / melle sopōrātam et medicātīs frūgibus offam / obicit ; "The vātēs , seeing that his necks are now bristling with snakes, throws to him a cake that was made sleepy with honey and with drugged fruits"). She's a being in contact with divinities (with Apollo, specifically) and can prophesy the future, with Apollo's guidance.
I don't know the word soothseer, I only found "soothsayer", does it exist?
Holy men, if you mean clairvoyants, soothsayers, seers, were haruspices (plural of haruspex/aruspex)
But my opinion is that "holy men" is maybe too general. They would be called "Viri sacri"? The Roman religion didn't have "saints" as in the Christianity, Sufism, etc, so, I think "holy men" is too general, because you can talk about a Vates, a priest (Sacerdos), an auspice, etc.. ?
For "vates", Wikipedia says:
The earliest Latin writers used vates to denote prophets and soothsayers in general; the word fell into disuse in Latin until it was > revived by Virgil. Thus Ovid could describe himself as the vates of Eros
It's close. Vates and Haruspex. Haruspices only looked in a sacrificed beast's entrails to read the future.
The word "Vatican" comes from "vates", it was an holly site for Romans.
"We visit the holy prophet in town" was accepted for me, so holy soothsayer will probably work too. Holy has the meaning of "saint" I think. Maybe we could even have the "saint prophet", I will test it.
Both are possible translations of vātēs. The religious signification (seer, prophet) is early; the idea that this is a role for a poet (speaking for the community, not in his own voice) was revived in the Augustan age by Vergil and Horace ( = bard).
What Duolingo may accept here is an altogether different question, though.