I think MrAbdiel and I could confirm that Aleeana and Isaera are actual sisters, not half sisters.

And I don't think there's anything wrong with some extra postings. Especially seeing as we're in a conversation here. Do you normally, consistently talk with like 5 other people at once and backtrack to subjects that were brought up minutes ago by someone else because you were already in the middle of trying to understand someone else without having their speech drown out? Probably not...

So in short, I think you should feel welcome to respond to roleplaying. Just as long as the parties involved don't get excessively too far ahead of everyone else.