I don't know about the ones that didn't survive but the ones that are alive are fraternal.
Are the twins in your family history identicle or fraternal? Identicle twins occur ramdomly when one fertilized egg splits early after conception. As I said, this is completely random and is not genetic/family based.
if the twins are mostly fraternal, there could be someing genetic that causes women to regularly release multiple eggs - which is the objective of clomid.
It depends. Clomid should help more follies mature and thus could produce more than one egg.
If you are truely concerned, you would want to go with a monitored cycle while taking Clomid. I was told only a fertility specialist would do this and not an GYN. With a monitored cycle, sonograms are done to see how many mature follies you have that would be ready to pop an egg out around ovulation.
I have PCOS and we went with Clomid + injectables with a fertility specialist. I was also 35 at the time. I never had more than 3 follies that were ready. We got our dd with try #3 of IUI.