I will start with the Wikipedia definition:
Systematic theology is a discipline of Christian theology that
formulates an orderly, rational, and coherent account of the Christian
faith and beliefs. Subdisciplines are dogmatics, ethics and philosophy
of religion.1(Taken from here)
I will finish with Caleb's answer:
There have been reams of words spilled on that already, but generally
we know at least this: questions really need to start with a text, be
specific, and leave the door open for answers to take the text
wherever specific interpretive frameworks take it.(taken from here)
While methodologies are "on-topic", "doctrines" aren't. That means questions posed about the many Christian doctrines are "off-topic". That does not mean, however, that one cannot refer to a doctrine in understanding a text, or discuss a doctrine(for example: laying on of hands) when it specifically is mentioned within the text.
Obviously, as the rest of your question refers to a question you posed, it is a judgment call, and not everyone parses this issue quite the same. In your 2nd example, the scriptural reference, John 3:13-14 was NT, and therefore entirely "on topic" with reference to Enoch and Elijah, who are mentioned in NT texts as well.
As a 'Rule of Thumb', I always comment when I VtC a question, giving the individual specific references as how to edit their question to conform to site guidelines. There's no sense in "throwing the penalty flag"(in American football terms), when you haven't explained the infraction.