Corn snakes generally get between 4-6 feet, with females being on the larger end of things. That's not as much snake as you think it is. The largest I've ever been around was about 6 feet and maybe the width of my first 3 fingers slightly stacked. Normal for them is 4-5 feet.
I feed all of my snakes frozen/thawed (f/t) and none of them have had any issues with that. Any and all snakes can and will bite, eventually. Play with a snake long enough and you'll get bit. Generally speaking, it's not as bad as it sounds especially with the smaller species. There are many species of snakes that stay relatively small if corn snakes sound intimidating. Hognose, Kenyan Sand Boa, and Rosy Boas don't get any bigger than 3 feet, with some of the males and more petite females staying closer to 2 feet. There are subspecies of Kings and Milks that also stay in the 3-4 foot range. They're all very manageable sizes and not nearly as big as their length would suggest.
There are also Ball Pythons (often called Royal Pythons) who get between 3-4 feet tops. These guys are quite fat for their length. Gives them the big snake in a little body feel. However, I don't personally consider them to be a good beginner snake as they can be picky and finicky eaters. It's not really a matter of "if" but "when" and "how long". I love my pythons, but there's always that chance that they will randomly decide to go off feed.
I would be careful about Chameleons though. They aren't a good option for beginner herp keepers as they have very specific husbandry needs. I would recommend Leopard or Fat Tail Geckos, or even Bearded Dragons as a nice beginner's lizard. They don't get too big, are forgiving of mistakes, and can be tamed easily enough. I'm always a fan of tortoises and turtles. They have fun personalities.