My perception of Kevin has definitely changed too. It seems like he's mellowed over the years, but maybe that's just because the rest of the guys have grown up, so there's not such a difference in maturity in the way they behave. I think his sense of humor and fun have shown more since he came back than before he left. I don't write a ton about Kevin in my stories, but I have tried to show that side of him more when I can.
Sick as My Secrets is the first Howie story I've ever written, and it hasn't been as hard as I thought it might be. It's weird that I don't write more about Howie and Kevin because, of all the boys, they are the two that are probably most similar to me in terms of personality. They should be easy for me to channel. I'm just more drawn to the other three, especially Brian and Nick. I guess opposites attract!
I think the way I write Nick has probably changed the most. He used to exist in my stories only as Brian's best friend, and he was immature and slightly annoying and kind of dim-witted because that was how I saw him until at least Black & Blue era. Then after Now or Never, he kinda grew on me, and I started making him a main character and writing him as more charismatic and appealing, but still maybe a little dim-witted and overly emotional. But he was doing all kinds of dumb things in real life back then, so maybe that portrayal wasn't so far off. My Nick now is smarter and more mature, still hot-tempered but not so angsty, and I think it's because of how much real Nick has grown up in the last decade.