The new baby will make him feel displaced (and, he has been literally displaced, and moved out of his space), so I think we must treat our kitties just like children--give them extra one-on-one time and extra play time.
Have you considered putting up shelves for him to climb around higher, since he's been displaced? And, FWIW, the best cleaner I have found is Sink The Stink, a divers' product which I get for Zeke's problem. It takes away the lingering odor in a way Natures Miracle never did no matter what I did.
Another thing for displaced Mowgli, is to play with him a whole lot. Definitely, play with him for about 10 minutes a day--try to wear him out. I can't promise it will stop the inappropriate peeing, but it will make for a happier kitty. I use Feliway all the time, and it is not effective in our situation. Nevertheless, I spray it places just-in-case.
This is what I have been doing. I'm sure I cannot cure Zeke, but I must make this place liveable, not be traumatized when he does it, and clean up easily.
I have been putting up paper (Post-it Table Top Dry Erase Pad -Super Sticky) on the walls where he likes to spray (no prevention seemed to work, so I'm into easy clean-up. I place it low enough on the wall so that the bottom curls up and catches the pee if he goes there. I put plastic under there so it doesn't get to the carpet. Often I use Magic Whiteboard Cling Dry Erase Sheets to place underneath. I have one set of drawers he regularly sprays. I have my large rubbermaid tub lids in front of that and to the side, under which I have placed plastic.
Further, I have found battery powered Scat Mat (gives mini electric shock) helpful too. Come to think of it, problems started again some time after I thought he was "cured" and now he has found so many other spots to spray! (this wouldn't work long-term for Mowgli as once the baby starts crawling . . . )
Oh, and finally, last year I invested in a Hoover rug shampooer. I have wall-to-wall carpets, and I simply could NOT spend money on having people come in every time he sprayed and I couldn't live with the smell. Now, if he sprays and it eludes the papers and plastic, I just whip out the shampooer (it's as easy as vacuuming) and get the pee out, then I apply the StS solution (via the shampooer) and let it dry out, killing any residual smell as it dries.
I love a behaviorist here in the States, who has some nifty ideas about cats going to high spaces and their need for play, etc.
http://tinyurl.com/c29rceb Jackson Galaxy, cat whisperer
Hope this gives you some ideas!
Best,
MaryG.