I'm trying to create a minor mod for my game that creates some Holocrons for my PC to use. So far all I have done is use KT to extract the file "pl_fakeholocron.uti" and edit the name to "pl_darkholocron.uti" along with adding actual powers/benefits to the holocron -- the new changes show up in my inventory screen (along with the new description), but the attribute bonuses and powers are not applying to my PC in-game. What do I need to do to get the new bonuses to apply to my PC while he has the holocron in his inventory? Is this possible? Do I need to create a baseitems.2da file? Any advice is appreciated!

I pretty sure that you need to have it done through the use of scripts that are triggered whenever you pick up the item. Just remember depending on what you want to do, you'll be restricted whether it is for K1 or TSL.