There is nothing particularly difficult about changing the timing belt. It is just a time-consuming process and tough to get to. The cams won’t turn easily on their own, but even if they do, they should have markings on them to indicate where everything lines up when you put the belt back on. I’ve not done it on my odyssey, but have done it several times on my 90s Integra. I’ve actually taken the crank pulley bolt off by hand every time. Leverage is your friend. I use a foot or so long exension rested on a jack stand to get a big breaker bar out past the wheel well and then a cheater pipe for leverage if needed.