Question 3: lateral answer: in the symmetrical variant the issue of "how many people are being given other people to meet, and is this entire thing just a weird trick" begins to rise.

In fact, the probability of it being a weird trick is going to overshadow almost any other attempt at analysis. The first person to get 25 happens to be a person who is told they will meet someone who got 75, and the person who was told they would meet the first person to get 25 happens to get 75? Massively improbable.

However, if it is not a trick, the probability is significantly in favour of it being 75% still. Alice isn't talking to Bob due to the fact she got 75, she's talking to Bob due to the fact he got the first 25. Otherwise Bob would most likely have ended up talking to someone else.

The proper response at this point for both Alice and Bob is to simply decide that it is overwhelming probable that Charlie is messing with them.

I can produce similar variants which don't have this issue, and they come out to 50:50. These include: Everyone is told that the first person to get 25 will meet the first person to get 75.