Some sentences with "as well as" - which ones are correct ?

English as a Second Language English Vocabulary, Grammar and Idioms
1

[color=green]1) It is important to tell them about it as well as showing them how to behave.
2) It is important to tell them about it as well as to show them how to behave.
3) It is important to tell them about it as well as show them how to behave.
[color=green]4) Telling them about it as well as showing them how to behave is important.
[color=red]5) Telling them about it as well as to show them how to behave is important.
6) Telling them about it as well as show them how to behave is important.

Dear community,
which of the above sentences sound correct to your native speaker ears?
I can’t quite put my finger on as to why, but the green ones sound OK to
me while the red ones sound odd / not acceptable. Do you share this notion?

I would really appreciate if someone could come up with a rule on how
to deal with these kinds of constructions.

Thanks in advance
Spacemarine

2

Your instincts are correct.

3

Thanks heaps for the quick reply.

Does anyone have a clue as to why the red ones are not OK?
Is there some rule that I could stick to so that I don’t always have to rely
on my instincts / gut feeling?