It's hard to tell by her weirdly shaped baby fat face and crazy fakeup, and there aren't many body pics of her, but I think it's pretty clear she's put on weight in the past year. I do agree that more of a baby bump should be showing if my guess that she'll be due in June/July is correct.
Phil outright denied that he was marrying Kat a week or so before the shocking announcement. It's Phil, he lies about everything. Part of the fun following him is weaving through the constant bullshit.
I mentioned it in the main thread but might as well go over it in the thread proper. It wouldn't be a surprise she put on weight living with Phil. Look at his lifestyle and the foods he eats. It doesn't sound like she goes out much without Phil. We saw all of their friends in their wedding pics, so we know there's no social life. You saw how excited Phil got over a week of eating at CT pizza places, to the point where he talked more fondly about getting pizza than his weddings. We still don't know what her job actually is, but I doubt it is anything that's particularly physically engaging, so her daily exercise is probably the same as Phil, one day a week of grocery shopping and occasionally waddling around the mall.
Regarding the wedding lies, you're right that he lied, but he never said he didn't want to get married. He'd say stuff like it was impossible or he couldn't afford it right now, but he totally wanted to, with not so subtle hints that maybe if people tipped more he'd be able to do that. I don't recall him ever saying he didn't want to get married like he's doing with having a kid.
We also saw the amount of effort he put into his marriage. Phil is stupid, but not even he is stupid enough not to realize having a kid isn't something where he can lazily take a trip one day to his parents and have them pay for everything and it is done and over. Whenever Phil has to do anything, no matter how small, he'll bitch and moan and make it sound like the most challenging thing in the world. He did nothing for his wedding. I'd even go so far as to say he spent more time planning his pizza trips out than he did his wedding. He didn't have to scout venues, plan a guest list, deal with catering, hire a photographer, etc. It was just show up to see mom and dad to get a tax bailout, play dressup in an hour or two in the big boy clothes his parents picked out, and stay away from the pizza table long enough to snap off a few pictures.
Something that I didn't mention but has come up is the doctor thing. Like you said, Phil lies. His manager was always giving him his scheduled day off today. I don't think he's going to the doctor at all, I think he's just responding to being called out for lying about being sick. He went from being so sick he couldn't even sleep while he was sleeping in bed all day to being fine enough to stream the next day. After such a miraculous recovery the likes of which the world hasn't witnessed since Jesus rose from the dead (and Phil only did it in one day not three, because he's such a hard worker) I can't imagine why Phil would need to see the doctor. It could be for pregnant Kat, but if she's supposedly been pregnant for months she would have had way more than one visit, and I don't think Phil would be able to resist complaining about that. Not to mention I think it is more damning that his attempted days off fall on the same days he took off last year, and Kat just so happens to be home those days too. I buy into the anniversary/some kind of important day to them way more than the pregnancy/suddenly needing to see the doctor thing.
If Phil is having a hard time letting Kat get a cat, I can't imagine he'd jump to wanting to have a kid with her. Phil also hates things that aren't about him and that take away his money. He was the center of attention at his wedding and you know he was way more excited about delivering one of his trademark epic "take that" wedding tweets at his detractors, so he probably expected to gain thousands of subscribers and followers like his other recent epic tweet. Plus it not only cost him nothing, but it seemed to be a positive gain with his parents paying his taxes.
