If this is the wrong place, I'm sorry, please move it for me.

Ok, I don't have SimPE or anything like that, but if it's necessary for the following, I'll get it.

First of all,, on MTS2 I've seen people upload versions of the same Sim at various ages, however the (for example) teen and adult/young adult versions were "modified seperatly", therefore the teen versions do not grow into their adult counterparts. How can I change that, make it so the teen versions grow into the seperate adult/young adut versions (or even child versions into teen versions and so on, if applicable)? If not, how do I change to the other files (which can apparently involve more than just a change of hair and/or make-up) once the "default" aging-related change occurs?

Also, how, if at all, do I alter a Sim's family history and/or memories?