Need help with decision! Five designs... 1 color or 5? Please vote!

I've been working on some fairy drawings for a local clothing store. So far, I have 3 designs (some of which are still in progress). The plan is to create a SERIES OF 5 DESIGNS which will eventually be screenprinted on women's baby doll t-shirts.

 

Here's the problem: I can't decide on the colors! We have decided to print each design as grayscale on pastel colored shirts... but should we print EACH DESIGN IN ONLY ONE SPECIFIC T-SHIRT COLOR, or print EACH DESIGN IN THE 5 T-SHIRT COLORS shown in the image above? Obviously it would be easier (and cheaper) to print each design on one color, but what do you think?

 

Here is a larger version of this design on the blue t-shirt

 

You can view the pencil drawing of this design here

 

And the other two designs in progress here: Woodland Fairy , Mushroom Fairy

 

Thanks for your help!

 

P.S. I did not take this picture... I used photos from a t-shirt wholesale company and photoshop to create this mock-up.

Done