LazySageDao
Thx for the chapter :D for abilities i guess something like illusion manipulation would power scale well, future sight would as well at first it could be only a couple seconds or even shorter then evolve into full on divination, clone creation could work as well (for this you can do the shadow clone jutsu way or even more unique and make it into a hive mind ) a good one could be intangibility but only with energy or physical attacks and extra vulnerability to spiritual one's
A good one for Luna (assuming I am not to late) would be the ability to manifest imagination Into reality. Similar to The Scarlet Witch, but this would be an ability that uses cosmic energy to manipulate/create/transmute matter at a fundamental level. Allowing her to create anything and everything she can think of. This also gives you a good limiter on the amount of energy she can use at a time or limit it by atomic size; something like that.
since rowena had those experiences with void energy, you could give some energy traits to her mana after she enters rank 5. Luna, as a psychic, would gain some form of vision of the immediate future, like the haki of one piece observation, which well trained can see the future, something that doesn't need much concentration.