u/Condemned_Nation64

The BLU team was never mentioned in the comics, only Team Fortress (which are the RED team).

The antagonists of that comic are the Team Ajax (Team Fortress Classic mercs).

Blutarch hired his own mercenaries that presumably wears blue, but they are not the BLU team we are familiar with.

The Meet the Team series are canonically propaganda videos performed by the RED team. And the BLU team in that series are portrayed by the RED team mercs.

Does the BLU team even exist?

Yes, Blueprints, not Red.

What's so special about Team Fortress that they're used as the base for your entire robot army?

Lugunica's main method of transportation are still dragon carriages. Rem said that it takes 2 days to travel from Lugunica's capital to Roswaal's Mansion with a dragon carriage. A Subaru Leone RX Turbo could probably travel the distance in less time than that. With the help of magic, I thought technology would progress faster than what humans can achieve.

The name, the character design, the superhero? Can I legally sell Spider-Man merch without any problems?

Subspace Transmissions, Subspace Missiles, Subspace Tunnels, Subspace Rifts, Subspace Subspace, Subspace Toilets.

Is everything subspace in the science?

Katana, Whips, Swords, basically dated weapons in their standards, yet some people still use em' over guns. Why is that?

And is it possible to bind their souls to an armor if need be?