But the verse does not imply that any warring faction is...

But the verse does not imply that any warring faction is necessarily Muslim even though they say so by their tong.

There is no doubt that a believer can be killer of an innocent and also there is no doubt that such killer will go to Hell forever as the following verse testifies: “And Whoever kills a believer deliberately, his reward is Hell forever, and the Wrath of Allah is upon him, He cursed him and prepared a great punishment for him.”(3) The above verse does not exclude believers from that punishment. Whoever does so, is entitled to the same punishment be it a believer or an unbeliever.

I also think you forgot to think about the latter portion of the verse you quoted which was: “If then one of them transgresses against the other, fight that which transgresses until it complies with the command of Allah.” Talha and Zubair are entitled to this last portion. Because Imam Ali frequently asked them for reconciliation, but they killed his messenger when he was carrying The Quran to them as a sign of asking for reconciliation.

(4) So those companions are “Bagee” — transgressors according to the verse you quoted, and should have been fought as Imam Ali did, and they will be the companions of Hell forever. A brother mentioned that according to The Quran, Moses who was a Prophet of god was confused with the strange actions of al-Khidhr. But when at the end, Moses (AS) was told about the reasons behind those actions, he completely admired them.

Moses (AS) was a Prophet, but still, He could not see the complete picture related to these events; none of us is in the position of Moses (AS). None of us has a clear picture of what we are criticizing from the actions of our companions. I would like to remind you that brother that he is discrediting you the most important investment which Allah gifted to everyone which is logic (Aql). If I came to know God, it was due the using this investment.

If I found that Islam is the best religion, it is because I used my brain and concluded that the instructions given in The Quran are sound instructions and the regulations of Islam are the best among all other alternatives. If one discredits this precious thing, he will lose everything including his religion, and he will accept any irrational ‘fatwa’ as a religious command, he will accept some killers of innocents going to paradise without giving it a thought.