A squad of six pathfinders is fine I run a squad of 5 and plant them in the center of the table. What ever they point at dies no problem.
You probable won't be too happy with the Plasma/Flamer combo because you want that plasma rifle firing away all game so you should keep him back and out of flamer range.
As for the sniper team I find that they suck. They won't pin, they hardly kill anything, and they are way to expensive for what they do. If you want more markerlights I might suggest a stealth team with team leader plus markerlight and marker drone. That's two highly mobile markerlights with the stealth.