In our group people walked at different paces but it wasn't a problem - never too long a wait, and besides, the waiting points were usually for a morning or afternoon snack, or lunch, and in a spot that was relaxing and pleasant to be in. The guides generally ensured that one of them was with the front group and the other near the back. Not much dawdling!

I think this depends on how much difference there is. We are very fast walkers (we were 8 of the groups) the other 2 walkers were extremely slow, while we did not have to walk with them we did have to wait for them at points. These waits were in many cases in excess of an hour (after walking for about an hour). Sometimes the waiting points were ok sometimes not so good, had it been raining or any colder we would have had to refuse to wait as we were traveling with children. Having said that we only got really annoyed a couple of times because let's face it we were in the best place in the world. Our preference would have been to leave early, walk faster and spend the afternoons chilling in huts, playing cards etc, but our guides did not allow us this flexibility. Call and ask who is walking???

On my group (January) the group were of different abilities. You are pretty much walking a simple route so the guides did not operate with a leader up front and a back marker.

I do not think you have anything to worry about. You will love the trip and will not feel constrained by people who walk at a more leisurely pace.