I don't know that much about acid reflux and the vegan diet. I know milk, spices and citrus fruits can be triggers for acid reflux. Dried fruits are a good alternative to fresh fruit. Just avoid the ones with sulphites in their ingredients. I found a site with some good info, I'm sure there's more out there.
http://www.acidrefluxdietresource.co...vegetarian.php
As for getting a 7 year old excited about veganism, well, I'm pretty sure I have the world's proudest 7 year old vegan. I think he loves it so much because he's naturally a very sensitive boy and knowing that what he eats doesn't cause any suffering makes him relax a bit. We also do lots of exciting, very vegan things like visit Farm Sanctuary and occassionally splurg on vegan treats that we order on-line and which come in the mail. I am very proud of being a vegan, which spills naturally onto him and I point out to him all the good that vegans do for the world. It's a very happy thing, being a vegan.