EmmBee,
Two observations based on past experience:
(1) Intensify your search for reservations on rec.gov beginning 1-2 weeks before 9/3. Considerate people who no longer intend to hike will cancel their reservations, and some of those printing permits will reduce their party size. BTW, permits not printed by 10 AM on 9/3 will be cancelled, which is particularly useful if your two hikers are present in Lone Pine then.
(2) Several years ago, a friend obtained 15 reservations in the February lottery for a day hike on her brother's 40th birthday in July. Come July, all the hikers (including her brother) had bailed on the hike. Seeing she was the last one standing, she also decided not to hike. I encouraged her to cancel her reservation for 15, so others could use them. Your group sounds solid, but possibly over the next three months, two will bail, leaving the needed two extra permits.
Jim