One thing you should consider before pooling miles. What is your redemption goals. Not all redemptions are best with Aegean, especially those surcharges.
Another option is do your kids a favor and let them build their mile balance. Unless you are not taking your family on a flight ever again, cashing out miles make sense.
I didn't understand your second point, sorry. Why in the world would I let the miles collect dust in those accounts? It's def prone to inflation (devaluation)
I target my CC spending on bank currencies, mostly Chase UR, getting a minimum of 1.5 value, and not having to search for avail awards. In fact, those miles earned were from flights paid with Chase points. It would have been a challenge to find 6 award tickets with points on 1 flight.
When I fly with my wife or alone I will look for business class and then transfer to miles, did it in the past with united.
In any case, it makes much more sense to have them in 1 account so it's more readily redeemable. I did credit to Aegean mostly because they have this "together" feature. I would have had to travel 10 times with the kids in order for them to have a meaningful balance of miles in their accounts.