Technically? Yes, Correto is it's own separate distribution that Amazon manages porting upstream changes into. Same as how Azul's Zulu is a "competitor" as well.
Practically speaking, it shouldn't matter as they all pass the Java TCK.
Practically speaking, it shouldn't matter as they all pass the Java TCK.
2. Corretto and Zulu each have their own patch set. Corretto backports a couple of G1 fixes and Zulu backports Flight Recorder and TLS 1.3.