I actually gave Azula a son in my headcanon (which is in the middle of being rewritten on FanFiction)! ^^ However, he has light brown hair and looks like his dad (except he has Azula's eye color and her crooked smile). His father happens to be someone who is in the Avatar series, but who could it be...? XD Guess!
I think your concept his quite handsome. Despite there being very few fics/art portraying Azula in the maternal role, most people that do tend to give her a daughter as her firstborn, which irks me. A son just... I dunno, makes sense, and seems a more unique option. People commonly use the concept that Azula should have a daughter who shares her struggle as a woman to survive in the male-dominated world of war and elite bending. But it is just so old hat now. Giving her a son here is very refreshing to me, and I'm glad you did it. ^^
Love the pic! An instant fave!