Embiid and Okafor cannot play extended minutes together. Neither have the ability to defend the pick and roll, other than just icing the ball-handler and giving him open jumpers.
For all the intrigue around Embiid, he is slow of foot laterally. He is a big man who can defend the rim, but if you make him defend a stretch big, he is going to struggle, and if you want to be a good big in today's NBA, you have to be able to defend the perimeter situationally.
Can he be good enough offensively to make stretch bigs pay? Maybe one day, but it seems like trying to fit a square peg in a round hole if you are trying to make them play together.
It's be better to pick one, build around Saric, Simmons, and that big, and trade the others for young, experienced, qualities starting guards who don't need the ball in their hands a lot.