Do transformation bodies appear before a buddha reaches enlightenment?

Do transformation bodies appear before a buddha reaches enlightenment? So that the many bodies of Shakyamuni that the fan Wang ching (Sutra of Brahmas net ) claims Vairocana manifests may have appeared before our Gautama Buddha? If the Buddha bodies do *not* all manifest at the same time then can two transformation bodies of the same Buddha appear in what will be the same Buddha field, at different times? I'm interested because I want to understand the lotus sutra and e.g. its claims about the Buddha's eternal life.