No he is talking about Young Man NPCs, which is what the Male protagonist's male children that are born from female Natives grow up into.
No not at the moment since there is no way to get Young Man npcs to initiate sex with Yona.
You probably will be able to once the next update comes out in a few days, since the next update is finally adding romance and sex scenes for Man x Yona beyond the rape scene. So once the consensual sex scenes are added for Man X Yona, I am guessing Yona can dance to increase her relationship with Young Man NPCs, and initiate sex via dialogue like with any other sexable male character.
Just to clarify Young Man npc uses all the same animations as the male main character because it is the same character template. So anything the male character can do so can the the Young Man npc in theory. The only limit is whether the devs script a way for us to do so.
Since we're on the topic, I wonder if the devs might consider at some future time the possibility of increasing NPC disposition with methods beyond dancing. Maybe something like giving them better outfits, or better weapons, or bribing them with food... Sure, dancing is really only a minor inconvenience at the moment, but it
does get annoying when you're trying to increase the dispositions of a decently large group only to have to separate them and do it individually or with smaller groups. I also don't like the fact that animals/creatures have personalities... my first playthrough, Werewolf and Bigfoot almost killed each other because I didn't know about personality incompatibility then. Would have
really sucked to have lost one or both of them, because that was an organic playthrough; no cheat-levelling or cheat-spawning.