As her profile image shows, Luna still doesn't remember that she's a Mew, and is still disguised as an Espeon. Until someone is able to take down the psychic barrier, she can not do any form of transformation, but she is still capable of being a predator, should she choose to be.
None to note.
Celestial Luna(called Luna for short) was a young Mew being hunted down by Team Rocket, Team Plasma, Team Magma, Team Galactic, Team Aqua, and even Team Flare all at the same time. She was cornered and had no way out. So, she transformed into an Espeon, since it is the Pokemon most like Mew and then ran into the forest, using her appearance to slip past, but, knowing they would all come for her again, she decided to wipe her own memory, thus forgetting who she was and staying an Espeon to keep herself safe and hidden. Thanks to this, only another Psychic-type can take down the barrier around her memories. Should one of these Psychic-types find her, it might be safe for them to take down the barrier, should they know it's there.
Regarding her transformation capabilities
Mew (Default)
Just like any normal Mew, Luna can transform into any Pokemon at will, but unlike most Mews, she can become much more than that. If she sees someone, and memorizes what they look like, she can transform into them at will. Of course, she doesn't do this without permission to use this transformation in the future... The one problem is...it can only be female. If the target is any other gender, then when she transforms into them, it will be a female version of them.
She can also become a herm or male, which will alter the gender of the transformation when becoming someone else, agijinka( Gijinka Form Image ), an Anthro( Anthro Form Image ), and even a Macro( Macro form image ) or Micro Mew.
More Information Here on Luna's F-List (NOTE:Family and recent Events shown on F-list profile don't apply to Eka's Chat)