Somewhat related to Gale's remarks, we see every pod that the companions were held in, Astarion's is near where we find him, Karlach's is up river from where she's hiding, we potentially free Shadowheart from hers, and there are three four in the first chamber apart from our own, for presumably Lae'zel, Gale and Wyll and one other. Much more than some off the cuff banter, Wyll's timeline seems to be the bigger culprit, he doesn't mention the ship much and I always got the impression he'd been with the Tieflings for a while.
I was literally just reading something on reddit about Wyll's timeline. I'll copy/paste it here.
The following quote was written by someone named agouzov on reddit, and I think it's a good summary:
Here's my understanding of the sequence of events:
-Wyll is born to a noble family in Baldur's Gate. He is raised by a domineering, emotionally absent father.
-Wyll seeks a way to rebel, tries his hand at recreational thievery and is caught.
-His father decides to teach him a lesson and enrolls him in the Flaming Fist mercenary company, which is the main law-keeping military force in Baldur's Gate.
-Wyll proves an incompetent soldier, and is mocked and shunned by his new comrades in the Fist.
-While defending a small outlying village against a goblin attack, Wyll is beaten unconscious and left for dead. One of the goblins takes his eye as a trophy.
-A cambion lady named Mizora contacts Wyll and offers to make him a legendary hero, which would allow him to get revenge on the goblins, as well as show off to his father and former comrade in arms. Wyll accepts, promising his soul to the Nine Hells after his death as payment.
-Using his new powers, Wyll develops a reputation as a legendary hero. Stories about "the Blade of Frontiers" begin to circulate in the region.
-Wyll begins having second thoughts about the infernal contract and tells Mizora he wants to renegotiate. They have an argument, during which a mind flayer ship suddenly shows up and captures them both. Wyll gets a tadpole inserted in his eye.
-After the ship crashes, Wyll scampers off in search of Mizora and stumbles upon the Grove before Tav. His reputation as the Blade of Frontiers earns him a warm welcome there.
-Wyll meets Tav and joins their party.
-Mizora contacts Wyll through his Stone of Sending, telling him she was captured by goblins. She offers to let Wyll off the hook regarding his side of the contract if he comes to her rescue. Enticed by the prospect of keeping his warlock powers without losing his soul, Wyll tries to push Tav towards attacking the goblin camp, pretending he's doing it to protect the tieflings.
-When his secret motivations eventually become known, Wyll confesses everything and asks Tav for help rescuing Mizora, who has been shipped to the Moonrise Towers in the meantime.
