Is this legal?

Player A has two monsters face up on the field and so does Player B. Let's say Player A's monsters are two Berserk Gorilla and Player B's are two Archfiend Soldier.

Player A: Normal Summons Magical Scientist and pays 1000 life points to bring out Ojama King and then activates Creature Swap. He pays another 1000 life points and brings out another Ojama King. This is the part that I am wondering about.

Would Player B be forced to lose both Archfiend Soldier or would he beable to swap an Ojama King for the other Ojama King? I can't find the ruling on this, I already searched for it to and everything talks about positions of monsters with Creature Swap.

yes he can give u the ojama king as it is now his monster. the better thing 2 do would b 2 first swap a strong fusion like dark blade knight or balter, then swap the king.

You didn't get the point of such a weak fusion. It was for a Beast deck that TLK used and he wanted a ruling on Swap.

Since your opponent still had 2 monsters to choose from at the resolution of "Creature Swap", then yes, he/she could have given you back the Ojama King that you gave them earlier.