[Blue gumdrops]

I received a male 6 week old Yorkie and we named him champion lol. Well when we picked him up his previous owner told us he drinks warm milk and he eats Cesar savory which is okay. Well the Cesar he likes and it's actually a dog food that he can eat for now since he hasn't gotten his teeth grown in. Anyway I googled if milk is okay to drink and I guess not? What should I give him to drink? Or do dogs just eat? Idk I'm sorry this is the first time that a dog is my responsibility and I'm trying to make this the home for him. He is so small he's the height of my pinkie and I'm a female. Our house is kinda chilly and I ready that Yorkies don't have fire but they have hair and only have 1 coat and champ was shivering and trembling since its kinda cold in my house. We put blankets on him but he moves around a lot so we turned on the heater so he's at least warm. He isn't trembling or shaking after that. But about every hour at night he would sleep wake up and start whining. I think it was because he he to pee because I picked him up and put him down and he peed. So he knows to tell us when he has to go. But My mom said she wants to keep him indoors because he's just a baby and he's so small. She fears he will get sick but since he isn't potty trained we're going to house train him and eventually buy pads. Should I start him now? Or around what age should I start potty training him? I would also like to know the difference when he's hungry and when he's just whining because he just likes to get picked up and put onto our bed. I always assume that when he whines it's because he's hungry since he starts licking my fingers along with my sisters. Or is that him just being friendly? Another thing I want to address is that he's been biting my sister, my blanket, his self and I. It doesn't hurt because he doesn't has teeth but I would like to know if it's because he doesn't like us and he's trying to show us that it if he's just teething and we should buy him a toy or something to chew. If anyone could answer my questions and not leave anything out that would be great oh and his claws or nails are kinda sharp and get stuck on his bed along with my shirts. Idk where to stop cutting. Should I get his done by a vet or should I do it myself?how much does it cost for that alone? And with grooming his hair isn't long but I read that grooming is essential fora Yorkie so is it fine to brush his hair with a regular brush or is there a specific brush for it? Anyways I'm sorry to waste anyone's time but this is to make sure he has the best care