1. The powers will fall under the same stipulations in which they were created: however she had interpreted the robes to work is how they continue to work. So if she believes it only works on surface level thoughts, then that's all it does, for example. However, who they work on will be on an individual basis (some characters have mind-shielding abilities, for example) and also reliant on player permission.

2. If the robes are swapped, the powers will still work but they work as the original owner interpreted them. Their belief/understanding of the robes is what shaped their magic and creation, so it would remain the same even if someone else wearing them might think they work a different way.