Christmas Day - Stuffing

[TakingTheStairs]

I'm really hoping some wise MNetters can help me please.
I intend on making sage and onion stuffing balls for Christmas day. But in the interests of organisation, would it be okay to make the mixture and prep the balls on Christmas Eve?
I wasn't sure how the onions that had been sweated would hold up. I would make them, then cover them and put them in the fridge until they needed to be cooked.
I'm planning on using this BBC Food recipe

That should be fine. All that will happen is that any cereal ingredients will soak up any spare moisture. The onions shouldn't change at all.

Thank you!