Referencing just the number in a GameObject's name?

I think you want an array of Flower[ ] in your Bouquet.

The Bouquet probably doesn’t care about the type, and if it did, it should access one single public int flowerType; in a single Flower

That way you can make as many flower prefabs as you like, just change that public ID on each one.

Alternately you might consider ScriptableObjects:

ScriptableObject usage in RPGs:

Usage as a shared common data container: