Yes, give it a try. Tofu is bean curd from the soybean. I use it in spaghetti as a meat replacement, but not alot of it. As with anything, if you start out slow and find out what your tolerance is, then you can proceed safely.
Yes, rice milk is a bit thin, but I like the taste on my cereal. I tried soy, but it tasted like chalk (like milk o magnesia) to me. I tried almond, and wasn't too keen on that either. It really is an individual taste thing.
Why are you so limited in what you can eat right now?