All of this is based on my understanding of the new behaviours - and although I wrote the documentation that you have seen, I may not be 100% correct 
In the case of 1, “if a reply is sent” implies in_reply_to_status must also be set. In which case yes, full text would contain all of the replies, text would not (replies would be metadata), both users should be notified.
In the case of 2, you’re falling back to existing behaviour, so yes, both of your statements would be correct.