No. It depends on their intent. If their sole intent is to aid Theo, they're subs. If they have planted as equal allies, then they are allies. But I bet you Theo will get all the mines, all the conquers, all the spoils, and ofc he is the only one in the group red boosting. You wouldn't red boost if you weren't a sub.
Also, placement. You don't plant on top of each other if you intend to just be allies in solo. If you do that then you plant across a continent, with the purpose of controlling that continent. And each member gets a set amount of mines in that continent, so that you all remain competitive and get extra resources.