Also, I assume that given being integrated into a new group of young females he will more quickly evolve into a full silverback male (perhaps in a shorter timeframe than we would otherwise expect).
That is true also- at least its very likely.
The Djanghou group at Howletts was created simply by placing the nine year old Djanghou- then a spindly undeveloped animal, with several females younger than him. They simply grew up as a 'youth group' with no friction and then started breeding as they matured. Other groups in Europe, e.g. Apenheul's, were originally formed in the same way and the AF forms new groups in Africa this way too.. It does represent another, though rather unnatural, way of forming a new group. But lots of things with Gorillas in captivity e.g. male groups, aren't natural anyway...