L.M.
I have some experience with children with cleft palates being a birth doula. I'd suggest limiting the Pediasure. I believe it has tons of sugar and maybe even high fructose corn syrup. I'd have to look at my nutrition notes about your situation before giving you specifics.
As far as speech therapy, please consider coming down to Johns Hopkins. They have amazing staff who are great at language.
And lastly, and equally as important, I'd encourage you to look into cue speech rather than sign language. Takes 2 weekends to learn, literacy is so much better than with children who sign. If you want any more info. about any of my suggestions, please contact me.
Trust your gut!