You've got good instinct looking at Specialized. You won't go wrong getting any of the listed models. Don't worry too much about the width/style of tires. It's an easy thing to change. Most MTB-type rims will take a 1.5-2.5 wide tire. If you find yourself mostly on pavement you can put on a lower-resistance (thinner) tire.
I actually just got my wife an Ariel and it's fantastic. It's a little too "comfort" for me, even, but it suits her well. If you're really going to be 60% on dirt, I'd avoid the Carmel or any true comfort bikes. And you may find the Hardrock too aggressive for leisurely rides. Assuming you fit the bike, "aggressiveness" of a bike's stance can be eyeballed by the horizontal and vertical difference between the seat and handlebars. Look at the three bikes you've mentioned side-by-side and you'll see what I mean. If you're overweight and buying bikes for fitness, an "aggressive" stance may be hard on your back and wrists. The ariel/crosswhatever is a good mix. But most of all, don't get hung up. Buy a bike that fits and ride as much as you can!
Good luck.