When filling out applications to open accounts with wholesalers, they ask for a Shipping Address. Since I will be shipping to various FBA warehouses, should I be giving them an FBA address and if so where do I get that information?
If a supplier is asking for your shipping address on an application, you should either provide your business address or just write in "Multiple Warehouse Locations In The US"
When you place an order with your supplier you will need to create a shipping plan in Amazon and then provide your shipping labels (with specific FBA warehouse addresses) to your supplier for shipping.
The address you provide on an application should not be important since you will be shipping to various US warehouses (like many large retailers do).