[quote=@Shard]
[@Divine Darkness] Does she automatically know how to activate the power when she gets it? For example, if she copied Casper's power, would she know how to duplicate items from the get go?[/quote]
In the case of Casper's, or any mutant's ability that needed to be activated, Haruna would not know immediately how to activate or what the exact trigger was. If she spends time with Casper and sees/learns how he activates his power then she would know she has to touch an object before duplicating it. This does not mean she'll be able to turn it off the first time she replicates his power...

[quote=@Shard]Passive powers such as enhanced strength would probably just kick in, but active powers would seem to be harder to manage. 
[/quote]
In case of enhanced or even super strength, depending on the mutant from whom she is replicating the ability, sure, it may automatically kick in. She'll definitely have to adjust to her new found strength or a lot of things are gonna get broken.

If she were to replicate Angel's (Warren Worthington III) power of flight, Haruna would actually sprout wings from her back which I'm sure would be quite painful and a bit traumatic.

If she were to replicate Cyclop's optic beam ability not only would she have issue with trying to control the power and range of her optic blast, but she would also have to keep her eyes closed unless she was given some ruby quartz lenses or risk injuring/killing others because the power would always be active.

On top of her own current power limits Haruna also picks up all the weaknesses, limitations and side effects that come along with the power she replicates. Unless she is presently in the room with the mutant of which she wishes to copy from or has knowledge of who exactly was in the area before her, Haruna has no way of knowing what the limits/side effects of the replicated power will be until she replicates it. At the start of the game Haruna only has the ability detect mutant [u]powers[/u], not individual or specific mutants.

[s]EDIT: I will edit my CS to include these limitations to my character's ability.[/s]

EDIT: I have now edited my CS to hopefully make my character's limitations detailed and clear.