Try the White Velvet cake, it is so good. I have made it several times and it always turns out “yummy and moist”. Although I have to say this description applies to all of Rose’s cakes.
Rose recommends any non-chocolate buttercream, glaze or fondant, so the mango buttercream will work well with it. I have made mango buttercream using mango puree. I follow Rose’s directions for Fruit Mousseline on pg 245 in the Cake Bible. The brand of mango puree I use is “Les Vergers Boiron”. It is from France. Hope this helps.