As a fellow Lightroom user, please allow me to say that I LOVE these photos and that I can tell that most of that has to do with the skills of the photographer and not the software
The first one is fantastic. The processing matches her expression, with those wispy curls as a perfect frame. Seriously, this would be one of the first images in my portfolio if I'd taken this.
The top-right-hand-corner is the only one that bothers me a bit. The pink of his shirt bleeds into his shorts, and his shorts bleed into his leg. Since it's both colors, I'm going to guess this is a clarity/fill light issue. Also, his face is kind of an odd color.
You might consider desaturating the magentas in the bottom-right-hand pic. The bit around her eyes makes it look as though she might have been crying previously.
These are tiny issues compared to how much I love the overall effect of each one. It looks as though you've mastered processing to suit the photo.