The information on Megurine Lulu is still being gathered. Currently it states she was created to be a sibling or youth version of Megurine Luka herself. Just like Sakine Meiko is to the official Meiko, both characters can be viewed as a separate mascot or a youth version.
The genderswap Megurine Luki is simply a male derivative based on Luka. He wasn't given consistent stats or attention by much of the fandom beyond artwork. You can say that he's in his 20s for your personal portrayal of him, but I can't add it to the page due to age suggestions not being common. Plus making him 20 would match Luka's and that causes a slight conflict.