I think Zachary/Zacharie is cute, but it's best shortened to just Zach in my opinion :D Very chipper name and just overall nice sounding.
However!
Dante would also be a good pick because it sounds more... noble and laid-back, and male rats are generally MUCH more relaxed than females (if they're fixed). They're more content to sit and laze around and cuddle, while females like to climb and crawl and dig into clothes more often than not.
But those two are definitely great choices, I love them both <3 Good luck with your new rat!