My understanding is that all females ceres go brown when they go into condition.
So even being albino, she'll still get the tan brown cere.
Someone will correct me if I'm wrong.
Until you learn Starlight's personality and what her condition periods are like, it's impossible to say what to do.
I would say that getting a second cage that's substantial enough to keep either one of them in full time would be the best way to go and you won't have to worry about anything should they not get along and have to house them alone.
Either having them always housed alone, or keeping them together and splitting as needed is workable.
From my own personal experience, I used to keep my birds in pairs, one male and a female per cage. They used to come out for play time together very often. I have since changed this to have them all live together.
Since getting budgies, I have only had to split a pair up once and it was just for one week. You can have the odd bird who will be dead set on breeding, but that's the minority and following the steps in the When we don't want eggs sticky should be enough to keep breeding at bay.
You will be the one who will have to make the judgement later on as you see your birds nature.