Crazyguy,
I feel so bad for you! The pressure you are feeling is obvious in every word you wrote.
In addition to understanding where you are coming from entirely, I think you need to be talked down a bit - just for today.
Someone - ANYONE encouraging your child to call them Dad is crossing the line. Aunt or Uncle? Maybe/maybe not - other factors could be involved...we have an old lady never married no children who teaches piano and has for 40 years. All the kids call her Aunt Sue" and now the grown folks take their kids to "Aunt Sue" for lessons. That is a situation where it seems appropriate for all involved.
I guess you have to look at the intent behind it huh?
In your case, I cant think of one single good intention in telling children who have a father in their lives to call someone else Dad.
That needs to stop IMO. Having said that, I think there is a way to go about it that leaves you in charge and with your dignity intact.
1) Act dont re-act
2) Begin with the end in mind.
Just because you are right doesnt negate the need to be calm and courteous. Wait till you feel in control of your emotions and calm. Use short simple sentences and dont go off in other directions about other issues. Something simple such as " I am their Dad, but they can call you "Br Bob" instead of Br. Jones if you prefer" (assuming the mans name is Bob Jones)
As far as the other issues you raised about this being war and such, those are long term discussion issues that many people will have thoughts on so I will stay away from that except to say that war means different things to different people. I feel I am fighting a war for my family who is "in" but I am on the surface, calm and agreeable. I will stick with this tactic as long as it works. When it doesnt work anymore I will re- look at what to do next.
In my personal life experience, head on aggression rarely works so I dont use it. I usually view life as a series of compromises and try to get some of what I want while allowing others the same courtesy.
When you mention your oldest son is smart and might ask a question such as if you believed you would see the dead person again or weather he was going to be resurrected...
that looks like a GREAT teaching moment between father and son!
Why cant you address the second part first and say "son the truth is no one knows if people will be resurrected or not. It is something that many cultures have stories about and many holy books talk about. In our culture the Bible speaks of this and many people feel better and more comforted by the hope of that. That hope - when no one really knows for sure - is called faith."
As for the first part where he asked what YOU believe, just tell him but keep it as simple and brief as you can and let HIM ask for more detail later.
I know you dont know me and I am not trying to tell you how to handle your situation but I just feel your pain shows in your words and I can see why you are so frustrated.
Sometimes just knowing we are NOT crazy for seeing what we are seeing and feeling what it makes us feel, is a comfort in itself.
Hang in there!