Are chests in your children’s bedroom safe or do they respawn

When you join a "college" or a "group" like Winterhold Academy or company in Windhelm, they give you a "dorm" room.

When you notice that some room might be yours open the console (tilde key) click on wardrobe to select it and type IsOwner and you should see who it belongs to exactly. If it is you, then it is a safe place to store your items.

Also to make sure you can put item in container and go away for 48h that is the time items know to disappear.

Note:aiming at bed and seeing if it is red or not is easy and quick way,but it is not the most accurate since you can sleep in some beds even if you don't own the cabinets...

You may have had a hireling steal or loot the item. This doesn't count toward your own items stolen, but the item will still be marked as stolen.

You may have looted an item which was already stolen when you found it. (I'm not certain how this can happen.)

You may have pickpocketed the item. This counts toward your "Items Pickpocketed" counter but not "Items Stolen".

Note: Picking up a stolen item in your own home won't increment your stolen items counter. I've tested this, but you may want to save first anyway. If the red in your inventory bothers you, bonemeal and ingots lose their Stolen status when crafted using Alchemy and Smithing respectively.