The Yor, like all races have a unique tech-tree for their race.
Getting Barren-Colonies much earlier than others is one of their special feats.
Some others get Aquatic-Colonies just as early.
Spies cannot steal techs. They are to sabotage their buildings by rendering them useless until a counter-spy is used. You can also just use them for intelligence or defensively if someone blocks your buildings. (The AIs usually gang up against whoever is dominant with their spies to cripple his economy as noone can get as many counter-spies as all the others can combined)
Oh, and there's no real need to play the non TA-Versions. It's pretty much the same but lacking some features... like those spies or asteroid-fields for instance.
Another edit: You can steal techs by invading their planets. But if you invade their barren worlds without the tech and you get some other tech instead of that, those planets will really be useless for you until you get the tech.
