But it does FormCreate twice 
It does exactly what you told it to.
1. Create form 1, it executes create
2. Create form 2, it executes the create of form 2, first inheriting form1's create then the rest of the code
If you have specific needs/requirements then you would have to specifically state these.
from one of your earlier posts:
My request is to inherit FormCreate from Unit1 in the newly created Unit2, so that it first calls FormCreate from the newly created Unit2, but now it does not execute the Unit2 code. Or is there a way to create a Unit1 window in Unit2?
Thus switch the inherited create and show the message to accomplish that what you wrote above. Though it is still unclear for me if you want 2 separate forms or only one.