Reddit mentions of Getting Your Specialty Food Product Onto Store Shelves: The Ultimate Wholesale How-To Guide For Artisan Food Companies

Id buy this book https://www.amazon.com/gp/product/0692213287/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 . It talks about costs and similar issues. It's not an exact match for catering, but you'll see a lot of the same problems in a food product like costs, kitchens, marketing, etc and how to manage those costs.

You will need all of those things you listed so start saving for those.

In my county, we have a search feature to look at restaurants and you can approach owners to use their kitchens off hours and see where that takes you too.

Then you need basic marketing stuff

• website
  
• professional organization fees
  
• group fees like chamber of commerce type stuff
  
• business cards
  
• pamphlets
  
• sample menus on nicely printed paper
  
• an office or somewhere to meet