[La Princesa]

you really need to confine him to a small area of your home at first and start by taking him out in the morning and maybe every hour if you have time but make sure its on a schedule. Thas just until you figure out how long he can hold his pee then adjust your schedule to taking him out every 2-3 hours and make it longer until you get him on a good schedule that is appropriate to yours. once you train him, then u can give a bigger area of the house , but do it in small amounts, Like mine could only stay in the living room, then i let him go in the living room and kitchen area and so on. Mind you my apartment is small. He is not allowed in my sons room which is empty anyway because for some reason he marks up my sons room if my son is not in there. also get a book or go to a website that gives more details on how to do it. Look at different teaching methods and find the best that works for you. i found that most methods are the same with little changes here and there.
I got my boy when he was a year old and he adjusted well to his name change, cause i am sure they called him something at the breeders home for a year... but yeah make sure your niece is ok with this.. if your main focus is for your niece to be able to interact with him i wouldnt change his name