I'm not crazy about the aftertaste of the Crystal Light. That is probably an individual thing.
Soy isn't a problem for me, it is for some people though. I like the kind with extra fiber in it. It is hard to eat high fiber with the diet restrictions I'm on.
I had the Nissen Fundoplication last October. I'm basically off all carbonation unless I want to suffer from horrible gas bloat because it is physically impossible for the air to come back up after I swallow. It is really tempting to "cheat" when I have those cravings, but I know I will end up paying for it. I did try a small icee a few weeks ago. It was small and I didn't have any problems, but I worried I was pushing it.
I'm limited right now from eating raw fruits and veggies, but at one time I was able to do some summer smoothies. Fruit, soy milk, ice. A meal and a drink at the same time. Most people do well with the bananas in the drinks. Bananas upset my reflux though. I used to do OK with some berries.
I have lots of frienRAB who like the almond milk. If you don't want to try soy, that may be a good option.