[HELP] First time dog owner

Hello,I recently moved out of my parents home and got a dog. He is a 1yr Maltese/Yorkie mix. I've had dogs before but my parents and siblings did most of the work since I worked a lot.Here is a bit of backstory. I found Cricket though Craigslist. His story is kind of odd but I am not sure if it is entirely true. He lived with his first family for his entire life. They had two service dogs and he was the family pet. Apparently one of their extended family members got sick and his old family was leaving to be with the memeber as they went through the final stages of end of life care. So they were giving Cricket away but taking the service dogs.I've had Cricket for 4 weeks. These are the issues we are dealing with:-Mild social anxiety.We are working on this. He just recently stopped barking when I leave him in the (big) bathroom when I go to work. But if I am in the kitchen and he is in my bedroom with the door closed, he howls. I want to eventually get to a point where I can leave him to roam in my bedroom while I leave for work.-Potty TrainingThis is an odd issue. He doesn't pee out of fear and he doesn't poop in the house. He will pee in the doorway right before we get ready to go outside for a walk and then he pees while we walk down the stairs to get outside. It's frustrating because by the time we are outside he doesn't have to go anymore. He doesn't even sniff for a place so I don't have any warning signs. He just sort of goes. I don't know what to do aside from possibly carrying him until we get to where he needs to be.-Toys and TreatsHe has a chewy KONG bear, a bone and two balls. He doesn't care to play with them but he will rough house with me. He sleeps most of the time and doesn't try to get into anything so I don't think he is bored. He doesn't like dog treats either unless we are in the bedroom. This makes it difficult to train him using positive reinforcement because he won't eat treats even if we are on my balcony or in the kitchen.I really do care for Cricket and he is a good dog. But I need to get these issues ironed out. via /r/dogs http://ift.tt/2qEv9vc