I would deffinately suggest doing this with options...It's fairly straight forward for the core units (an option directly changes the min/max)...In the case of the Aspect warriors you set the initial min AND max to 4 and add an option that resets both of these to 8 and adjusts the cost appropriately...Unofrtunately I'm not the best person to ask for the cost advice as I'm currently having my own dilemas on this account...
For child units you can set some invisible stats that are nothing more the placeholders for multiple children...
When you select the option that adds, say stealth suits, that same option sets the value of one of the stats to indicate the min/max model for the child unit (in the case of stealth suits to 3)...Then you can give the stealth suit unit an option that is only live when it has the tag "runtime.child" and the size script mentioned earlier...I would have script which sets the unit cost to zero if it contains the tag "runtime.child" and procede to add the cost through the option...That way you don't have to worry about cost per model...Very useful for the afformentioned stealth suits...