One of my colleagues is retiring on Friday and I have been asked to make a cake (not being paid). Anyway, I have a few questions if you wouldn't mind advising please.
I am planning on making a sheet type cake - two swissroll tin sized lime sponge cakes layered with mango, lime juice and creme freche filling, topped with some more of the creme freche and lime mixture. My first question: is it possible to pipe creme freche? I wouldn't be doing anything particularly fancy but would like to write Happy Retirement on it. Would it hold or end up melting into the rest of the topping? Would mixing in some powdered sugar or something help or would I just be better writting it in melted chocolate on parchment paper and then putting the letters on top of the cake when I have the topping put on?

Secondly do you have any suggestions on storing the finished cake over night? I only have a very small fridge and have never done a cake of this surface area before so haven't worked out how to keep it cool enough to keep the creme freche fresh. (I have a very very tiny freezer so any method with freezing wouldn't work either) It will be only from 11pm ish until 08:30 the next morning because there is a fridge in the office I can use. I have a cardboard carry box I can use to transport/store it but will I need to use cling film to create a better seal to keep the cake fresh?

Thank you for your help and sorry if they seem like stupid questions, I've never had a semi-formal request for a cake before!