It would be enormously difficult to create a sentient AI. That's why the Automata Corps uses volunteers rather than creating robots. It's simpler to just transfer a mind. 

As for the creation of the body: it would be more likely to build the body mechanically. The only reason to use silver in that manner would be for aesthetic. 

So all of these things depend on how wealthy your characters is. If they were a talented Magi, they could have ordered the building of the pet, and undergone the enchantments themselves. I believe you were going to be a Magi anyway, so this is likely the route you would take. 

A quick note about organic silver skin: to do a whole body in silver skin, it would need a conventional mechanical framework underneath(a skeleton, basically). Otherwise it would collapse easily.