My former coach had a booth dinette and there were seat belts in the forward facing seat for two people. This was a factory install. If your dining area is a booth, then I believe your plan would be OK with adequate reinforcing of the anchoring area. To be honest, however, I cannot remember if the frame of the forward seat itself was reinforced with steel tubing or not. I do remember that the framing was wood, and not particularly robust.
Larry, Eileen, and Finley
2004 Alpine 36FDDS
Third motor home, first Alpine, no need for another.