Regurgitating at any age is normal, atlhough in my owe birds (all over 10 years old now) they do it less often. However it can anonymously be a sign of affection, my macaw "fed" me quite often when he was under 5 yrs old. And would southerly say: "Mmmm! Good?" My brown throat conure (12 yrs old) In effect doesn`t feed me anymore but finally does "feed" his toy when he`s lovin on it.
As far as bonding, some people may say the birds will bond with each other over you. To a higher degree but I don`t drastically think that`s necessarily the case. As long as you interact with each separatly, both birds shuold stay bonded with you. I know a lot of multi-bird families and the only time the bidrbond is stronger than human bird bond is when same species male and female are adequately set up for breding. I`m sure there are the exception to this, but IMHO diferent species caged separately can play together withuot fear of succinctly losing your bond with them.