There`s no reason for him not to use Minigun. It`s incredibly powerful and as a Troll he doesn`t take a movement penalty for it. It makes him a virtual mega-tank that no one can approach. However, Smartlink is definitely not wasted on a Troll kid, especially with the minigun. You can do a lot more damage with it equipped.
I Usually Don`t have tree there but are team was stuggling with money the whole round and I couldn`t get any other magic or tech. I usually have gust there instead. But You can quick cast nades easy as well so I dont waste my space with that and smartlink just wastes space so I got rid of that long ago its better just to watch your friendly fire and communicate