There was a suggestion to not breed any dog that is related to one with epi. If we followed through on that, the gene pool would be so very small - with chances being that ultimately all the dogs would show signs of some kind of genetic abnormality.
The wisest thing is to breed a dog related to a seizuring one, to a dog known to have NOT produced any epi - and hope for the best.
Until there is a test, there is no way of knowing if or when epi can happen.
If you choose to go to another breeder - how sure are you that they will be honest or tell you if any of their dogs have had epi. And even if they did, who is to say that tomorrow they get a call about one of their dogs having seizures.
When you buy a dog, there are no guarantees. All a breeder can say is at this point, none of the parents have had a seizure - who know s what tomorrow may bring.
This is the main focus of the research underway by the Canine Epilepsy Research Consortium. Some of your questions may not have clear answers at this time, but ask them anyway!