Space after headline and body copy

There is a way, if you're willing to use a baseline grid. 
Set the start increment of the grid to be the baseline of your first line of body text. Make sure your body text is aligned to the baseline grid, but your head is not. The space after the head and the space before the body text becomes irrelevant.
If you find this too restrictive to apply document wide, you can use a custom baseline grid on a frame-by-frame basis, if necessary defining this as an Object Style.

If this feels like too much trouble, alternatively you can make 3 variants of your body first paragraph style, one that follows a single-line headline, a second that follows a two-line head with more space, etc.

Having the body copy and headlines in separate tex frames would be the easiest way to accomplish this. Other than that, I can't think of specific paragraph or frame settings that would set the text this way automatically.