This is adorable. I love that Lu Ten seemed to be both trying to find reasons to like Zuko and, at the same time, trying to remind himself why he shouldn't. His cluelessness about Zuke's limitations (no playing in lava!) is rather appropriate, given the fact that Zuko is probably the first half human he's encountered.
Re: Lu Ten and young Zuko, breakable
Also, baby Zuko is the most adorable thing ever