As the "parront" to a CAG, I can speak from experience here. Definitely glad you're doing your research. So, yes, a lot of Greys "don't talk" but a lot of them do. I would say more than half of the Greys I have encountered do indeed talk, some more than others. The difference, though, is that you don't want to
expect the bird to talk. My Grey is a rescue, she is about 13 to 14 years old, we're not exactly sure.
Greys are still a delight, even if they do not talk, many are great whistlers, and with their intelligence they can learn a lot of tricks. Chance loves the clicker and she loves a challenge. I do advise though that this species of bird is highly, highly intelligent -- in my opinion -- rivaling that of dolphins, and they are capable of sneaking out a cage and finding ways out of the cage!
Still, there are pros and cons. With high intelligence comes neuroticism and sensitivity. Greys are indeed very sensitive and they tend to like the "status quo," they don't like change all that much. They're like the Parmenides of birds in this regard! My CAG loves being on her play perch and staying there, although on her terms, she will enjoy cuddling and watching TV with me.
Since birds are warm blooded, I would say keep the house temperature at least 65 degrees. I'm not sure about your area, but I keep the house warm, but then I live in a colder, wetter climate. I do use a small, electric heater in the room. It does the trick just fine.
Greys need a lot of stimulation -- my Grey's cage is in front of a window -- and leafy greens to tear apart as well as some good toys are needed. They need good vegetables in their diet, Chance loves carrots in particular.
Lastly, Greys are dusty, but I don't have a humidifier. I just air the house out naturally with windows open and vaccum my hard wood floors often.
Message me any time if you ever had any questions.