The first reaction is the thermite reaction used in pyrotechnics.
The last one reaction is used to obtain calcium cyanamide. This substance is widely used in agriculture and the production of pharmaceuticals and other organic compounds.
The other reactions have no practical outcome.
What is the practical outcome of 2Al +Fe2O3 → Al2O3 +2Fe
CaC2 +Fe2O3 → CaO +2Fe+2CO ↑
2CaC2 +5O2 → 2CaO + 4CO2 ↑
CaC2 + N2 → CaCN2