Basic bonsai soil could be any type of soil, as long as it got good drainage, good water-retention and good aeration.
You can use the same soil mix for deciduous trees, for your Ficus tree.
But again, i recommend: Akadama, Pumice and pine bark.
Some people dont recommend japanese soils in areas with hard frost in winters. Because akadama and pumice breaks down.
You can use Perlite instead of akadama and pumice. About 50% perlite and 50% pine bark.