Hi Nic0074
When tiering cakes, you are always best to use a sturdy cake to take the weight, especially if you are hoping to get away with using dowels.
Personally, I use Madeira cake which is similar to Pound/Vanilla cake just for the versatility factor, and I have used it without dowels. (Although in fairness I would always opt to use dowels depending on how much weight you wish to put on the top tier).
A vanilla cake would be your best option for stacking and fondant, although if you wanted to, you could perhaps use vanilla cake on the bottom and do the top tier in the mud cake. It's all up to you depending on what you feel comfortable with.
I didn't use dowels in this Beauty and the Beast cake, but due to the cake and...