I don't think it's crazy; the general idea sounds delicious. However, assuming you are brewing 5 gal, you're looking at a beer with an ABV over 6% and a final gravity of at least 1.012, which doesn't sound too summery nor very saisony to me. If you were to do something like:
2.5 light lme
2 wheat lme
you would have a beer with gravities around 1.045/1.009 and an ABV around 4.5, depending on your efficiency and allowing for the greater fermentability of grain vs extract.
I would also probably cut the 60 min hop addition in half, which would cut your total IBUs from 70ish to 45ish. 70 IBU might overwhelm the subtleties you're looking for from zest, late hops and saison yeast.
Feel free to alter or disregard any or all of this. It is your beer, after all.