I would use the stripe but leave the purple and take out the really light blue (first one next to print) That way you have some textures throughout your block - this is alot risky but you might try it and see how it looks. Also you blocks would need to be offwhite or cream to use with the stripe - Is the backgound on print white or off-white/cream.
I am not a big fan of mixing whites and creams in the backgrounds but thats just me!!! Be sure to let us know what you decide!!!
try laying fabrics as if its a large block - pyt your other blocks next to it and put floral next to whichever blocks it will be up against If alternating blocks spread floral fabric out large enough to fold bloick fabrics to look like your square and then place your other squares below. If print fabric is spread out enough you should be able to see it on both sides of your layout which gives you a better idea of how it will look (just a suggestion)