Can male pigeons use splayed legs on their backs?

Yes.

The outer eight or the inner eight are not directly related to whether the male pigeon can step on the back, so it can be stepped on the back.

After the male pigeon successfully steps on the back, he will usually follow the female pigeon. The two pigeons will stay together and keep singing. The male pigeon will follow the female pigeon to step on the nest. If there is If other male pigeons come to pair with the female pigeon, the male pigeon will drive them away.