Instead of "supercritical", you can say "gas" for N2.
35bar and 0°C is a boiling condition for CO2. At equilibrium, you would have a partial pressure of 35bar CO2 vapour in the gas phase, to which a partial pressure of N2 gas adds, so equilibrium is impossible.
The out-of-equilibrium proportions depend on the process and are more difficult to determine. If for instance CO2 is fully liquefied at 35bar and 0°C and you add N2 at 35bar and 0°C too, then liquid CO2 will stay at the bottom and gaseous N2 on the top, but CO2 evaporates slowly (without boiling if the pressure exceeds the liquid-vapour equilibrium pressure) and the total pressure rises above 35bar, for instance towards 70bar if the volume is constant.
"Superfluid" has a different meaning.