If you wanted to compress the Harfoot story, you could have either the Stranger leave alone right after he is discovered at the party, or you could have the Stranger, Nori, and Poppy leave together at that point.

The downside of speeding that up all the way to the three leaving would be that the Stranger suddenly becomes more verbal without the confrontation vs the mystics to explain that.

Once more, I’d also caution against the complete divorce of the Harfoot story from the other threads because it seems to be one of the only counterpoints of hope while everything else gets darker and darker. Hope is a big deal in Tolkien, and I strongly suspect that this plotline was invented by the writers to keep that going while the Southlands, Eregion, Kazad-Dum, and Númenor are all falling.