Congratulations! For question 1 - yes you can attempt to feed the second time f/t, but don't be surprised if the babies don't eat. Sometimes it takes two or three feedings before they switch over. 2) If you have veins in that egg, it should be OK. Sometimes they don't dimple until right at the end and some eggs take longer than others to pip.
congratulations again! That first clutch is always exciting!