I'm making a 3 tier, plain jane flavored cake - chocolate bottom, and yellow middle tier. For the top I wanted to do a zebra cake but was wondering if I could take the extra batter from my other 2 tiers and use it for the zebra cake? Or should I just stick with that recipe as is? Additionally, would that type of cake still work well in a 3" deep pan?
Thanks!

I don't see why you couldn't mix the two batters for the top tier. Are you making your tiers 3" tall or are you using two 3" layers per tier? I bought 3" pans and hate them. All of my cakes are 2" layers and I always do at least 2 layers per tier so that my cake is at least 4" tall. I just like tall cakes because I have more room to decorate and I like the way it looks.

About the top tier, people make marble cakes all the time that would be the same principal using both batters. Right?

You can use the 2 batters. I use 2 different batters for checker board cakes all the time. I don't think pan size matters. I usually do 2- 3" cakes in a tier.

Think that should look pretty neat... cause then you are incorporating
all the batters, white, chocolate and a"mix-up" Lol!!

Saw a tutorial somewhere showing the Zebra cake and how
to do it, would love to try that myself sometime.

We make marble cakes all the time and have done so successfully in 6" pans.