Influence may be a goal of lying, but it may also be a motivation for honest communication.
If your intentions are self serving, or anyway if you are covertly selective in what you tell to others, if you use fallacies, or if you outright lie, you are probably doing wrong. There's a word for that, and it's manipulation. Influence doesn't have neutral connotations in English. Much on the contrary: when you say someone has influenced you, or is/was influential in general, you're praising, not condemning them.
Full neutrality is impossible. You should keep neutrality as a general aim, while recognizing you're more biased than you realise.
More specifically, arguing equally for and against both sides of any war is not neutral; it's a futile attempt guided by political correctness. My first impression on reading that is that you're overreacting to typical western (esp. American) good vs evil rhetoric.
You can teach about a war without making explicit moral judgements about either side. There are many reasons to study a war that don't require you to discuss ethics (for example, you may be studying socioeconomic motivations and impact.) Or, if you want to discuss morals in a non judgmental way, you can describe the system of values that was current in each side at the time of the war.
That said, using the narration of a war as an illustration of some point in ethics is no worse, per se, than making such point in first place. In general, one side of the war will conform better than the other to some system of values. As a parent who is transmitting your child a system of values anyway, making a taboo of stating explicit judgments on either side of a war is pointless.
Hiding your beliefs from your children just not to influence them is a form of lying, and it's futile IMO. Do you have to make up cover stories about where you're going when attending church? Do you have to tell your relatives to keep the secret? Ridiculous.
And anyway, where would a 4 year old get his first ideas about religion from? Will they discover the Truth by themselves from cogito ergo sum? Nope, they'll be marked by the next influential person they meet: a teacher, a friend, etc. How is that any better?
Just stating your beliefs, while acknowledging the possibility that you're wrong, is a very honest thing to do. The child will grow to make their own opinion before it matters for any practical purposes anyway. That's what my parents did with me, and I stopped believing in God at around the same time I stopped believing in Santa Claus. I never felt pressured either way, and I carry no trauma that I know of.