Don't be too upset if he won't let you put a bow in his hair...I think the earlier you get them use to it the easier it is.
Pochi hates having bows in his hair and will pout and act like he's dead til you take it off him and the same goes with clothes. He will purposefully try to pee on them so that I take it off him.
Daisy and Choppi both don't mind bows and clothes but I started them early with it so they are use to it.
As far as training goes...are you pee pad or going to take him outdoors?
I think at this point outdoor training is probably easiest for him to learn since he's older and if he does mark he can know that it's ok to mark outside just not inside the house.