I too have different alters of varying abilities not related to their perceived age. In the end I suppose that's what alters have.... a "perceived" age, rather than an actual age. Because in reality they are split off parts of a 36 year old or a 45 year old or a 65 year old or whatever age the person with DID happens to be. They are -not- actual children. They can't be assessed as -actual- children. I do believe their skills and abilities will be whatever they need(ed) to be, regardless of the emotional and physical age they perceive themselves as.
In regards to animal alters, I don't think they even come close to possessing the skills and abilities of the actual animal... but rather they -believe- they possess the skills and abilities of the animal.