1) Of course it is ... it's personal!!!
My only thought would be, should it be "A Flower" or "Flowers"? (you mentioned your top variation is to make it look like flowers, and hte basket looks like it has several flowers in it)
2) The flannelette will act as your batting. Remember you're not going to have a puffy quilt! Spray or hand baste the back to the front and do your quilting. MTS's suggested pattern flows nicely with your pattern.
3) Spray baste the flower block to white cotton and then stitch it together as one, as you make your quilt back. Once your quilting is done, nothing will move. And the extra piece of cotton won't add any thickness to worry about.
4) You might consider whether you want it hand stitched onto the quilt or sewn into the backing as you are doing your flower block. If you have someone that could machine embroider your message, I'd consider going that route ... it'll be long lasting and durable. And under the conditions, you never know how it will be washed.
How special that you have cared for this young lady and want to give her something special to acknowledge her achievements! :)