Will there be any way to access the old art again? The fact that all the old scenes are going to be reworked makes me worried about updating my game going forward
Not every single art from previous updates will be reworked. By "old art" we mean art from 2020-2021, when the game had just started and our current lead artist wasn't as experienced as he is today.
As a matter of fact with 1.8 we're mostly done with reworks besides very few things like backgrounds or Evelyn's stuff (those artworks are also from that 2020-2021 timeframe) which we have decided not to rework until we rework her entire route.