If you're still beginning I wouldn't recommend going for a mixed build, if you want to go mixed build as a beginner especially when it comes to either Mage or Succubus, then you'd want Physical build to be the one mixed in first since it doesn't require any Combat Skill or Personality to get the most out of its damage, unlike Mage and Succubus which requires a big amount of grind.
But if you really want to know, in order to effectively play as both Mage and Succubus, you need to not select any personality since selecting a personality locks you out of some traits.
To better use sex skills you need to first raise Lona's Constitution trait point (to about 20+), farm sex level (about 800+ times sex skill use to get the recommended acquired sex level) and select some traits like Prostitute (gives 25 innate sex level), Whore of Babylon (more than double the acquired sex level, not to confuse with innate sex level) to a certain point where she can effectively do good sex skill damage (Nymphomaniac personality gives the same amount of innate sex level as Prostitute but since you wanna mix builds we're gonna ignore this).
To better use mage skills you need to attribute a huge amount of trait points into Wisdom.
Here's the endgame build I'm using on my Lona along with her sex level that allowed her to do those things in all those videos