French Oven: It is obvious that you can only make Creme Caramel. Sadly, that means that this will be using your melting pot full time, so you can't make other recipes. You will only be able to use one oven at a time.
Cake Oven: You can easily make both Snowball Cake and PBJ cake continuously on one oven, but PBJ Cake will allow you to have two ovens baking more constantly due to PB taking only an hour.
Pie Oven: With chocolate ganache out of the picture, you can make Peach Pie a la Mode. But with only one appliance, the Vanilla Ice Cream will take all four hours so you only need one oven.
Ice Cream Machine: Because your ice cream makers and melting pots are working full time, Raspberry Gelato is the best option and of course you can only have one oven.
Here are the costs to buy all the ingredients, recipes, and appliances:
French Oven: $1,350,000 for gold leaf, $2,670,000 for Creme Caramel= $4,020,000
Cake Oven: nothing
Pie Oven: $1,800,000 for peaches, $700,000 for fancy cream, $3,150,00 for Ice Cream Maker, and $3,900,000 for Peach Pie a la Mode= $9,550,000
Ice Cream Machine: $4,350,000 for Ice Cream Machine and $1,750,000 for Raspberry Gelato= $6,100,000
***the price for these for you might be different depending on what you already purchased and which order you buy stuff in.