Does any body now anything about launching a heavy progress from Kourou ?
You'd have to build a MIK specifically for it. I don't believe it would be worth it. Specially considering that it would be a 100% Russian labor, and I don't think they would get any significant extra performance to 51.6d. Only thing would be simplification of drop zones.
Yeah, no technical benefit at all.
I don't think a new MIK would be required, but certainly jigs and other GSE would have to be sent from Russia to South America, for no particular purpose. Unless someone were planning a new Russian space station at 8 degrees inclination.