Just wanted to pop in to say I enjoyed this discussion in this thread, and I think it speaks to something the game is currently doing quite well.
Now, trying it all together and delivering satisfying reveals/resolutions is obviously the key bit that Parian has to do, but it's certainly promising. The game does lay things out pretty well in doses between character chat, key notes presented to read, as well as the more general books and such.
Having said all that, it seems pretty clear to me that ShadowHeart being resurrected out of her time and being a Dark Justicar of some sort is a very strong likelyhood. Her memory suppression, strong emotional response to children, armour, response to historical triggers, etc points clearly down the path.
I find it hard to convince of a character history where these things are present where SH is actually of the current time. What the details end up being will be interesting to explore, but however they move around the edges the core path seems pretty locked in.
The bit that fits the least clearly from my plays of EA so far is the timing of when everyone was on the Nautiloid, and when they got their tadpoles. The idea that there are several different paths for different characters - some captured by the means shown in the opening cinematic, some captured as a response to raids on the Nautiloid, some stowing away (?) - makes it tricky to work out what's going on there.
So correct me if I'm wrong, but the general situation we open into is:
Nautiloid is on some mission. It has on board the artifact known as the weapon, which is in SHs hands, though she is restrained.
Tav, and LZ are already on the ship, in pods, and we assume also Astarion, SH, Wyll, and Gale. There is evidence of an internal battle on the ship recently, which seems to have been taken back under control, and so Tav and LZ get the treatment.
I'm assuming that SH, Gale, Wyll, and Astarion either receive the treatment now also, or have had done previously.
It's unclear who knows what about the weapon, but it seems that the ship is known to have it, and more Gith soon attack. In the pursuit the ship runs through the hell's, before finally jumping back (presumably heading home to Moonrise Towers) and crashing.
This questions, how does SH end up on the ship, and have posession of the artifact, seems the most tricky to answer.
Gale & Tav at this point have "just standard captures" possibilities.
LZ has the "captured in a failed earlier attack on the ship" possibility, or a "captured when/if the ship initially stole the artifact" possibility.
Karlach has a story of when she joined, though the timing there makes the treatment question a bit odd.
Astarion and Wyll are a bit coincidental with their links, so I'm not quite sure what to make out with them... But it's less obviously awkward than SH.
With SH one answer could have been she was serving on the ship on the behalf of the absolute, but that doesn't all line up with the "mission from Shar' and 'return to BG' side of things.
I'm curious if I've missed any clear answers to the situation.