Mr. Bonsai Kitty

Lately Bonsai has been a total ass. He's taken to yowling at all hours of the night, and day. He walks around the house yelling at unforeseen objects, and at times being really aggressive. I wonder if he is just really stir crazy and wants to go outside, or if he's starting to get old and losing his mind. No amounts of threats or dousing with the water gun seems to shut him up. We're leery to take him outside (supervised) because it will just promote more of the yelling. He's also taken to running laps around the house, like he did when he was a kitten. He does this in the middle of the night, which would be fine with a normal cat, except this one is a small elephant and you can hear him across the house thudding along. (And this house is not at all sound proofed, you can hear Chachi running too.) When he decides to rest at night he must be within inches of your face, which is not at all convenient for me, who has to get up a dozen times a night to pee. I understand that me not wanting him in my face is selfish, but once settled if he is disturbed he starts his running/thudding and yelling routine all over again.
Seriously I am at my wits end. As it is already I am having a tough time sleeping, so being woken from blissful sleep by my yowling cat is driving me nuts! Adam has the ability to either ignore him, or sleep through it, which is so unfair.
I've thought about getting him a no bark collar that you would for a dog, but I'm worried that his purring would set it off. (He purrs loud enough to wake me, but I won't begrudge him his purring.) In the middle of the night groggy with desperation I've wondered if getting his voice box removed would be an option, but I know I couldn't do that to him. I wouldn't get him declawed, so how could I put him through that? In any case I might lose my mind.
In our other apartment we would lock him in the far bathroom when he decided to have a yelly night, but we don't have a room here which works like that. In the new house he'll have his own room which should work though. However we don't move for months....
As for his aggressive behaviour, he's just been quicker with his claws with me. Mostly if he's laying on the ground and I step over him, he grabs my legs. I don't think he's trying to be mean, but his claws are close to three quarters of an inch long, and sharp. Then today he was sitting on the chair in the living room and he just freaked out and gave chase to something imaginary, leaving a huge gouge in the chair. (new. leather....) He's still patient with Chachi, and I'm not worried for the baby, and hopefully by the time she's a toddler he will have mellowed out again.
So does anyone have any ideas? I don't want to get rid of him. He's old and I don't think that anyone would love him as much as we do, and Chachi would be so lost without his big ol' buddy. Or am I destined to sleep with a water gun for another 10 years?
Hmm I wonder if this is just a kitty midlife crisis?