Hi--
The difference between early & late transcendentals is when the exponential and logarithm functions are introduced. In the early version, they are introduced quite early, but in a way that leaves some details unexplained. In the late version, a more rigorous explanation can be be provided.
The two multivariable versions contain the corresponding single variable versions, but no single version contains all the others. There are really 3 sets of material: single variable early transcendentals, single variable late transcendentals, and multivariable. The multivariable portion of each book is the same; the differences are all in the single variable material.
-- David