1)
Why did Yoktan merit having so many children?
1.
Rashi: Because he made himself small, as his name suggests. 1
1
Perhaps this is another indication of Eiver's power of prophecy. See Radak for an alternate explanation of Yoktan's name.
2)
Why did Yoktan call one of his sons "Chatzarmaves" (lit. "the courtyard of death")?