In reference to the sunlight in Barnabas' coffin room--it was quite early, the first or second ep as I recall. The Old House was undergoing renovation and someone (David? Vicky) just opened a door and walked down some steps into a coffin room. Streams of light were pouring into the room, albeit none directly onto the coffin. Willie stopped whoever-it-was.
Anne Rice even made a comment about it at the time.
As for how to do the flashback sequence differently, I would suggest avoiding the seance altogether! Don't send Victoria Winters into the past at all, but instead show Barnabas having tiny flashbacks to what happened as he met different family members or encountered circumstances. Very Highlander or Forever Knight. On top of that I would have scrapped the whole notion that Victoria Winters is Josette reincarnated. Tis a cliche and frankly rather cheap. So much more interesting the way it was done in the original series, in which Vicky is someone Barnabas comes to love for herself.
On the other hand, it would have been tres cool for someone else in the present to have been reincarnated -- preferably a character with less to do, like Liz. If in fact she were Naomi reborn, and started have strange dreams that would open up all kinds of interesting possibilities.
But I also think the approach to flashbacks needed to be more than exposition. For every question the flashbacks answered, they should have raised at least one more.
IMHO