Few more details might be good to know: (1) is this for commercial preparation
(ii) how many days of shelf life is targeted?
Why is the option of pure ghee (for frying) if this is for packed fried onion - will that be economically possible?
This is commonly used in Myanmar cooking - They are usually packed in plastic polythene packagings.
Oil - with variety of oils available, so may be more details required on which oil might help since the flavour of oil might also make a difference.
-Any plans to add preservatives?
thanks