I'm back

with more questions...
1) これ… 双方黙らぬか。 What does らぬか mean? I got that the sentence is saying something roughly the lines of "This… both sides, quiet/calm down!"
2) What's the difference between:
a. もしできれば~ (If you can do it~)
b. できれば~ (If you can do it~)
I don't see what's the difference between the two structures as they are translated the same. Is one more dramatic than the other or... ?
3) What's the difference between:
a. たとえ世界が終わっても~ (Even if the world ends~)
b. 世界が終わっても~ (Even if the world ends~)
Same as previous.
4) What do the endings mean?
a. じゃ(なんでこんな若造どもが評議員になれたんじゃ!How was these youngster able to become council member!)
b. もん(うちらお金ないもんね。We don't have money.)
Those are my translations of the sentences. But what does those respectively endings mean? Are they just characteristic ending/dialectic endings that don't mean anything?
If it helps, I'm read a manga in Japanese, and those are endings that certain characters tend to use, which led me to believe that they are just characteristic endings, but I would like to confirm that and not misunderstand everything...
5) Can we use ん and のでtogether? I thought we can, but I was told it sounded weird by a native speaker…
I wrote ロサンゼルスは砂漠にあるんので、~
but he said this ロサンゼルスは砂漠にあるので、~ is correct, because you don't use ん and のでtogether.
Thanks!