But the MC is technically NTR'ing his uncle and the neighbor, isn't he?Beastiality, yes. There is already horse stuff in it.
As for NTR.... not yet. Your character technically don't have any romantic interest yet, other than their mother. You ain't exactly giving too much of a good example for it to be labeled as NTR. Maybe Netori since you practically are stealing another man's woman, but as for cucking.... yeah, nothing to really stand that on.