Hmmmmm... I've been thinking. Remember how after Bull's Quest, if we save the Chargers, Bull asks to meet with Inquisitor on the battlements and then two Qunari spies attack?
After it the Inquisitor is all like "you knew they were coming?" and IB responds that yeah, he did, and had Inky as sort of unwitting backup in case he couldn't handle things himself. Inky is not happy with this and asks why Bull didn't tell him/her ahead of time - and Bull asks, rhetorically, if Inky had enough of training to not give away that they both knew what was coming. We see from their expression that no, not really; Bull giving away the information might have ended badly for both of them.
I kinda wonder... seeing how IB and Solas are similar in quite a few ways, perhaps him not revealing everything to Inky (and not-really-so-secretly hoping or at least giving them a chance to stop him) may also be something he withholds for them to actually succeed? Like, if Inquisitor knew too much, or knew something without getting to proper context or understanding first, they'll likely fail???
I mean, if we're honest, Solas already did something like it, to an extent, in Trespasser, as I'm pretty sure that Solas let Inky and the team travel through all the locations with full intention to throw some light on his and elvhen past (opening even the eluvians that the Qunari weren't actively using)... So, even if Inky didn't piece together that Solas was Fen'Harel before reaching him, their trip through eluvians and elvhen ruins must have given them new understanding of the Dread Wolf and the past, at least to a degree.