Hook em?! :headbang:
I'd be concerned about heat in those resistors on the bread board. What's the value of the resistors and voltage input? Use P = V^2 / R to determine the heat being dissipated ... The electrical tape will greatly decrease their ability to shed heat, they really should be heat sinked, but if you have that bread-boarded rig in the air stream from the fans, you could be OK.
The welds look good enough for brackets, especially once you grind them down. My dad always likes to say, "a grinder can turn any old farm boy into a welder"...
Did you use a special plastic paint on the fans? did you actually paint the blades? are you optimistic it will hold up?
Your engine bay is like mine... Only yours is further from stock!