Welcome to the forum pwillems.
Sounds like you know your high level requirements and now need now to develop a more detailed scope that a shopfitter can quote against. If you engage them properly I'm sure they could help you with this, perhaps meet on site and describe what you want and they'll then be able to provide an accurate quote.
Seeing as though you're setting up a cafe, I would assume you already know the approximate costs of the coffee machine equipment you want to get, which has a huge range is price.
In my experience of seeing a few restaurants, bars and cafes established I'd say that once you have your quotes you need to allow sufficient contingency (at least 10%) in your budget for variations.