In Baldur’s Gate Descent, devil dealmaking seems very odd

Could use a recommendation for a source describing Elturel in detail before Descent?

Is it possible to read about the three districts of Baldur’s Gate without stumbling onto that juicy NPC intrigues?

BG:Descent into Avernus Platinum Edition unboxing! – Beadle & Grimm

If a caster uses Mending on an Infernal War Machine does that aid in repair efforts?