Neither of the coffe shops have what you need. Get two small coffees, one from each shop, and mix them.
At the first Queequeg's, next to the Talent Agency, they have no lattes. Get an infant espresso full caf. Go to the second one (out of espresso) and get an infant latte decaf. Click on either one in your item bag and you will be prompted to mix them into the large empty cup, creating the perfect mix.
(You could switch to the opposite caffeine on the two, full or decaf, as long as you have one with each)