Hello! I posted yesterday about supports for two tiered cakes and am so thankful for the responses.  I need some recommendations.  

I am baking a cake for a 5 year old's birthday party.  She likes the cartoon "Shimmer and Shine." The cake is for about 20-25 people.  I would like to make a single tier cake with 3 layers and two different fillings.  I would like to make a vanilla cake and have one of the fillings be a funfetti type of filling.  I may make a small pillow second tier because the characters are genies and in photos sit on a pillow/rug style thing. 

Here are my questions:

1.  For 20-25 people, with 3 layers what size diameter should I use for the cakes to make it enough?

2.  Anyone have recommended fillings that can also be used to crumb coat for underneath fondant?

3.  Anyone have a recommendation for vanilla cake that withstands fondant well?

4. Am I going about this all wrong, and if so what would you recommend?

Thank you so much!!

My reply is on the other thread.

Haven't see any other post on this so I will answer here: 

1.  For 20-25 people, with 3 layers what size diameter should I use for the cakes to make it enough?

A 10" round 6" tall should do that. 

2.  Anyone have recommended fillings that can also be used to crumb coat for underneath fondant?

Bavarian creme is good.  It is similar to pastry cream.  But then I'm not sure it would do well as a crumb coat as it would take overnight (or similar time amount) to dry up enough to be covered w/fondant.  You don't want the crumb coat to be completely dry - it needs to be sticky enough for the fondant to stick to it.

3.  Anyone have a recommendation for vanilla cake that withstands fondant well?

This is an excellent recipe:  http://www.cakecentral.com/recipe/7445/the-original-wasc-cake-recipe

8" round serves 20 and 9" rounds serves 26

@kakeladi ‍, I referred her to your WASC recipe, too - haha.  Really like it.

Thanks everyone! I'm so thankful for all the support and recommendations!