Jay, sounds like things are hopping at your house but in a good way. I'm Kaylee has worked out so well as a playmate for Guy.
Dexter12, re the whining: you'll probably just have to ignore him if you want it to stop. It's hard but he must be getting something out of it (attention) or he'd give it up. The problem I had with Bella was that she'd grown up without gates, had no respect, and just knocked them down. Tucker wasn't and still isn't really ready to have complete run of the house because he puts everything in his mouth. So I've just gotten really good about keeping the bedroom and bathroom doors closed, and keeping as much out of the way in the other rooms of the house. He's still picking things up but there just aren't as many option. I still use the gates for when I want to keep them out of a room for a short while, but otherwise I'm letting then run around the house.
The possessiveness is a more serious problem though, especially if you are thinking about getting another dog. At his age there ought to be a way to keep him from destroying his bed, but I can't think of one... Perhaps ask in a freestanding thread to get greater response? Re: taking toys away from him, the best you can do is to offer something of equal or higher value--a treat or an even better toy. But Ido think this could become a much greater problem if he's showing possessive behavior with his humans, he'll probably do even more when a new dog comes on the scene.
Getting another dog: yay! Dex will have a great time with a playmate. Both Guy and I did that, and several others on the forum, and it does give the first dog a great outlet for all that energy. Just choose very well if you get a rescue and make sure Dex approves. See my update following for why...
To all: We are bumping along here. I love having Bella here but she has changed our lives in bad ways I hadn't counted on. Having been kept in a back yard with limited human or animal contact, she's very insecure "out in the world." The dog she is inside our home--loving, sweet, funny and playful--is the dog should be all the time but isn't. So we're working with a trainer who is helping me socialize her in a safe way. The other issue I wasn't prepared for was that Tucker has developed resource guarding issues. He adores Bella but gets almost manic when high value treats are brought into the picture. He can be quite mean to her and to Tess. So we are working on that, too. The upshot of it is that meals are carefully orchestrated, we don't go out into public very often, I don't go to the dog park unless it's empty, and more. I really hope we can get a grip on these issues very soon because I want to have a nice summer and go places!
As I type this, the two GRs just effected a change of ownership of an antler with no grumbling. Tucker had it, and now Bella does. Perhaps it's all do-able!