You do need 2 troops to play any game. It's a standard requirement. Although you can split your
fw's into 6 man squads if you want. Giving you more points to spend on tasty stuff. You will also need a
hq. I would suggest a fireblade at this points level. Stick him in a
fw squad to boost their shooting and have him marker light all game with his bs5. I would drop the stealth suits as they aren't the best. More crisis suits are better. As for the configuration on your crisis suits. It's best not to mix weapons as you can have 2 of the same weapon now unlike in the previous dex. So you could have 2 plasma rifles for 4 shots at rapid fire range. By not mixing weps you maximise the squads damage output against particular targets. The only draw back is your giving them a particular role by doing this. But as a wise man once said, it's better to be a master of one, than a master of none

if your set on keeping the piranha then give it a fusion blaster and swap the seekers for a disruption pod. Having a 4+ cover save just for moving is insane. So to clarify what I've said as I waffle too much, you need 1
hq and 2 troops basic to play a game. Then work your battle force around it once you have those worked out. And don't mix weapons on your suits.