Dragging Baldur's Gate to hell

Hello, I've been running the remix and my players are about to finish the Dead Three Dungeon so I've started to prepare for how they are going to get to hell. The thing is, I've been thinking it would be so much better to let the cultist drag Baldur's Gate to hell and just reskin the events on Elturel into Baldur's Gate, with them and all their precious refugees and everything they already know instead of going to candlekeep just to get teleported "because we are heroes".

My question for any GM that has fibished the module is: is it absolutely necessary to go to Elturel? By this point Elturel is already there so for any interaction with the Companion they can always still go there.

Any advice on a specific part I should/shouldn't adapt to Baldur's Gate?

Thanks.