Bruce fights Steve while Richard fights Shang.....Richard beats Shang and helps Bruce fight Steve.....Team 1 wins.
Bruce and Steve are both quite skilled nearly as skilled as each other and a fight between them would be long and drawn out with Steve winning in the end. Richard and Shang are both master martial artists but Richard has better feats, so he wins his fight quicker than Steve beats Bruce which allows him time to double team Steve before Bruce loses. Their combined effort should prove too much for Steve and overpower him, Bruce Wayne and Richard Dragon win.
I'm not up to speed with Richard Dragon, but what feats does he have to put him above Shang-Chi? The latter has demonstrated super-human striking ability, speed/reflexes and durability on several occasions.
Between Cap and Batman, I would say Cap wins since it's a random encounter, if only by a small margin.