My 2year old son had bowel movement after each meal, the stool looks ok, is that normal? Too much fiber?

Not a problem. Most people in our society are chronically constipated. People eating a whole foods indigenous-type diet average 2 bowel movements a day, but there is no problem with having 3 a day. I don't believe there is such a thing as too much fiber, as I know of no evidence of any harm from a high-fiber diet.
Not uncommon. Soft stools after every meal in a 2yo is a bit more than usual but not a worrisom issue. I don't see where fiber has much to do with it. The digestive tract sends a wave of "move along"signals down the intestines after a meal & sensitive kids can go every time. Excessive volume (>cup or so/day), mucousy or bloody stools would be worrisome. I see more pbs in kids who don't go regularly.