So it will be a 5 tier wedding cake, with two of the tiers being cheesecake, three of the tiers being regualr cake, all iced with buttercream. Here is the sequence.
6- cake
8-cake
10-cheesecake
12-cake
14- cheesecake

With regular cake construction (dowels and cardboard rounds), will the cheesecake hold up (no smooshing tiers)? I am especially concerned with the bottom tier holding all of the weight. We are still in the planning stage, so we can re-work if needed. Just wanted to get some wisdom, if anyone has ever done something like this, and how it went. Thanks!

No, I refuse cheesecake weddng cakes due to the food safety issues.

But if you're going to do it, your support system carries the weight. It doesn't make one tiny bit of difference what the cake/cheesecke is, as there should be NO weight on the cake tier.

I've done several wedding cheesecakes but all the tiers have been cheesecake. These wedding cakes stayed in the walk-in cooler until it was time to cut the cake. With your cake I would be concerned about the two cheesecake tiers sitting at room temperature for several hours. Not only the safety issue but warm cheesecake becomes soft and unpalatable. Can you make two cakes? It's non-traditional, but couples these days seem to enjoy having something different. I've seen cupcake towers, dessert tables, and ice cream buffets instead of the traditional wedding cake.