That's not NTR, Ema was already in a relationship when introduced and never shown you interest as a potential lover. Which in my opinion sucks ass but it isn't NTR,
As far as Vicky goes, she's also not introduced as a love interest, she makes it very clear from the beginning that all she wants from you is a child your never allowed to be a part of. Again dumb as fuck but not being "taken away from" if Vicky decided originally to be a Love Interest then later on changed her mind, you might be able to make an argument that she NTRed the MC but thats far far fetching.
NTR means taken away from, Netorare and Netori, if Ema does later on start to show feeling for MC then that would be NTR as MC is taking her away from James (Netori).
But let's say instead James starts banging Anna and she leaves you for him that would be NTR as well (Netorare)
But Currently you aren't taking away Ema and Vicky isn't being taken away by someone else so there is no NTR neither Netorare (mc losing a Love Interest) or Netori (MC taking away someone else's love interest) so no NTR involved Currently.
Just characters that you can't pursue interest in. Your forced to choose between 2 Asians and a former call girl. Which to me is just meh they aren't that interesting and it seems everyone has a huge demand for your time yet aren't rewarded very well and crossing paths hurts you but it is the only way to get the most content, not suggesting we need Harem more so just the game is still new so there isn't much available yet.