I've had three or four Marlin 336's over the years. I keep telling myself I need a deer rifle, even though I have done most of my deer hunting in "shotgun only" areas. I'll buy a rifle, shoot it a few times, then think "Why do I have this?" and sell it. Then start over again a few years later. The last one I bought had the crossbolt safety. It was almost as much a non-issue to me as the "lock" on a Smith & Wesson revolver. When I didn't want to use it, I just didn't use it. Big deal.
When I buy a gun, I want to see THE gun I'm buying, I don't care who made it. Not a picture of a gun. That's one reason why I won't order online.
Would they work for a ten year old? How big is the ten year old? They're a full sized rifle, and fairly heavy, but my ex-wife used one with no trouble. She was about 5-3, but probably heavier and more solid than most ten year olds. Another reason to have the gun in hand first. You can try it on.