Yes, you've got this part.So when both players passed in succession. The last effect will take place first. Then if both player decides not to chain, the second Last Will now take place.
I think you've got it. After one effect resolves new effects can be added to the existing chain in the same way as when the chain was started. The last effect added to the chain will always be the next to resolve if both players pass. So an effect can resolve, and then a new effect can be added. Maybee two effects resolve, then three more might be added. It can go up and down, but the last effect on the chain is always the next to resolve. And once it resolves it is no longer on the chain.If one of them decides to chain, the effect that is chained will resolve and the chain goes up and down until the one that is 'most up' is resolved. Is that the way it should be?