Hi Newgirl,
I'm surprised you haven't had a reply to this as i thought a lot of the members were well into tropicals.
Both of these are 'tropicals' as you will be aware and as such won't like the cold/damp, so normal temp with airflow (but not draughts).
From my experience with Celosia (brains), i'd cross my fingers if trying to store it for a week. Sometimes it lasts ages, other times it just falls over. I don't think it likes too much water and definitely wont like being stored in a wrapper (the stems will rot quickly)
The Strelitza...that can depend on the quality/grade/origin. The nice one that has a full bloom showing should last ok if fresh. In theory, as the flower dies, another one should open up after it. I've never had much joy with this and don't count on it. If they are not showing color at all, then you may struggle to bring them on.

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