Your stats are, of course, great. For Harvard, they are just as acceptable as anyone else’s that make it in. Your ECs are decent - but nothing really stands out besides the short stories.
However, the legacy bit helps - a lot. A significant percentage of every Harvard class is legacies, some who aren’t even really qualified. Because of this, I would say you definitely have a better than average shot. I can’t give an exact percentage, but better than the overall 4.5 percent admit rate by a good margin.
Show them who you are and why you belong there. This goes for both what you write for them and what you say to your interviewer and how you choose to present yourself to them.
Best of Luck! PM me if you have more questions/want more help with this.