Don't think so, there's a Citroën R5 here, and Fiesta in RX and R5.
I think it's more that the World RX license seems to be a bit more like NASCAR (and IndyCar?) as opposed to more traditionally europe-based racing licenses. In the way that you can get the license for the series name etc. but you then need to deal with teams, manufacturers and tracks in addition to it. Which is said to be the reason why Spa RX won't appear, Spa-licensing is much more expensive.
So I would guess Hyundai or GRX wanted more money than Codemasters were willing to give.