Mazaltov!! What a wonderful Hannukah gift you've received. Both my daughters were born on Hannukah (3 yrs apart) and it's a wonderful way to celebrate each year. Hope everyone is feeling well and adjusting.
As for the feelings: the euphoria slowly subsides but the joy never goes away as every day brings something new that makes you enjoy them even more - even if you thought that wasn't possible.
Meilleurs voeux de sante et bonheur pour les nouveaux venus dans la famille G.
Another piece of advice (from a son) is to really be their friend from the get go, rather than just the head of the household/provider that commands/demands respect. This kinda goes along with someone else's suggestion of being involved in all their activities.