I can't speak to all of the questions you have raised since I've only had one grey myself, and when he came to us we already another dog (lab cross). He howled when we left him crated...it was loud and awful and I don't know how long it went on. It sounds like you do not crate yours. Some dogs like the crate as it makes them feel safe. Is there a crate she can retreat to? When we stopped crating him after a few weeks, he stopped. I work at home however.
Our grey is very reserved - that's just how he is. If his tail wags a couple of inches, we know he is ecstatic. He hangs out in the bedroom, where we all sleep, instead of where we are. That's his "lair". He's not much of a toy guy either, except when he gets up before his breakfast. He only likes to chew real bones and pizzles, primed with cat food.
Some dogs are the more "velcro" type. Maybe that's what you are looking for. It also can take them months (six?) or longer to settle in before they feel at home. Django really didn't show his silly side until we had him for 6 months. Good luck to you, what ever you decide!