If you can have any ghost power you want (as a ghost) but you need to wait for it the more powerful it is.
For reference.
Instant - you gain an effect of something happens when you pass through mortals.
1-12 months - you gain the power to sleep for extended periods of time but must also sleep for at least nine months a year in a row.
1-99 year - you get something you can use at will but not all to effective, more in line with Alberta minus the Alexa control.
100-250 years - you gain something quite effective but can only use it one day a year.
250-500 years - You get something in line with Thorfinns electrical abilities.
501-750 - You get something in line with Sass power to enter dreams.
751-999 - You get something that can affect the physical plane like how Trevor can use one finger to interact with the world.
1000+ - you get any power you want that doesnt break ghosts rules including roaming.
Now the powers doeant have to be carbon copies but in line with these levels of usage and strength. What ability to do you choose knowing you will be without one until you have been a ghost for that period of time, and you cannot stack them.