Or, they should get the shield technologies with less research time than others. Perhaps they should get a ship-sized version of the Arnorian planet shield in the end. I think Iconians and Thalans should have different techs though, with the Iconian defenses referring to Precursor technology and Thalan defenses referring to extra dimensions.
I felt the Iconians and Thalans should have the same actual components with different flavor text in the tech description. Seems simpler, and the components would be pretty similiar anyway, at least in my view: the current Iconian and Thalan tech trees both have a "few but powerful" theme, and I'd have something similiar here.
The Terrans probably shouldn't get any techs to do with the Arnorian planetary shield, because it's Arnorian. They didn't invent it and they didn't have a clue how it worked in the campaign.
The Arceans and Drengin could possibly have a similiar set of defenses, reflecting that they were the only races to have fought an interstellar war before the hyperdrive era.
The Torians could have weaker defenses, but with more passive bonuses (this is already slightly the case). It reflects both that they're new to advanced technology, and that, as an aquatic species, they have a natural edge at 3-dimensional movement most others don't. As long as there's no "evasion" feature in the game, I prefer to reflect things like this with passive bonuses to weapons and defense.