I am sorry that you have been waiting for a response. I recently just logged onto the site and noted that your question hasn't yet been answered. I am a licensed veterinarian with over 25 years’ experience and would be happy work with you if you are still needing assistance.
In all of my experience with cats through the years, I can tell you that I have learned all cats have their own unique personality and while you can influence it some, you will never change it. Some cats are cuddlers and some just aren't and never will be. Some are very vocal and others not so much. As they age, I have seen some tend to mellow out and certainly some do become more vocal. I have read and do believe that cats have learned to vocalize to communicate with humans as they use body language to communicate with other cats. If that is the case, now that he is the only cat in the house, he may likely start to communicate more with you.
I would continue to pet him when he is near, but always be in charge of the petting sessions. Do it a few times and then stop, before he tells you he has had enough. You want to make him want the attention and not shower him with it too much. As far as the vocalizing, talk to him all of the time, and over time, he may start to reply more.
I am also including a link to a website that offer suggestions to provide environmental enrichment for indoor cats. This has become a very important subject as we have now identified that many cat behavior and medical disorders stem from the fact that they are confined indoors and don't receive enough stimulation, This "stress" can lead to physical and behavioral problems. By enriching the environment, it can provide both physical and mental stimulation and make for a more well adjusted cat.
OSU Indoor Pet Initiative
I hope this is helpful. Please let me know if you have ANY other questions. My goal is to give you 100% satisfaction and if you are not yet satisfied, please reply so I can clarify for you.