It sounds all completely normal to me. It's likely that he just "discovered" that he could get underneath the paper towels, and it seems that he simply prefers that to the hide he has. So long as you're certain the floor of the tub isn't getting too hot, it won't hurt him to do that.

What kind of hide does he have? They have a high preference for really snug caves that "hug" them on all sides. If the hide is bigger than he is, he may like being underneath the paper because he can feel it all around him. So maybe trying some different sorts of hides....something that looks almost too small for him to fit into would be ideal. Put one on the warm side and one on the cool side so he can choose whichever temp he prefers without having to sacrifice security. (You may already be doing that....but I don't know, so I thought I'd mention it.)

As for the striking....again, perfectly normal. He's still just a little baby, and is the natural prey of just about every meat-eating critter out there...so even if he's used to you, it's very easy to startle them and cause a defensive strike because at that age, they're pretty much always on the defensive.

Crumpled paper towels in the enclosure certainly can't hurt, but may not be necessary.