I agree with you Mr. Zetetic Elench dam Kahveh, I agree with you 100% about being able to have a friendly and interesting conversation about religion. It just shows that people on both sides can be polite and respectful. It is also nice to talk to somebody who has convictions.
Christianity is, as you said to a large degree about being saved. And the bible does NOT SAY that unbelievers will roast in hell. In fact the passages used to try to prove this are taken out of context. Which is in itself an interesting discussion.
As far as being saved think of it this way! If I was going to build a house for you, one that you were to be truly happy with, would it not be true that there are several steps and procedures that I need to do, in order for you to be happy. First you would require that I put in a level, sturdy foundation, because without that, it's difficult to build the rest of the home. You would also expect that the framing be done correctly and to the local building codes... and so on.... Now if you told me, "Jason, I want this house to have a good foundation and good frame job." Then is that all I need to do to make the house a quality built home? The point is that there is not just ONE way that a person gains salvation, at least according to the bible there isnt.
John 5:24 is of curse one of the first steps to be taken to be approved by God, or gain salvation, whichever wording you wanna use. But just think, If you believe the Gods word, then will that not effect your actions? Like if you believed an asteroid was gonna impact the earth in 2-3 days, would your actions most likely be different than normal?
And according to the bible, when an individual becomes a believer and lives his/her life accordingly, then they make a dedication to God, which is symbolized by baptism.
As for faith and works, both are needed. Because a person CAN have good works, but not have faith, but a person that has faith, well works just come naturally. Thats why James said at James 2:14 of what benefit is faith without works, and says that faith cannot save him. But he later says in verse 18 that he would show or prove his faith by his works. It is not as if we can earn salvation in any way, it is a gift, it is by the grace of god. But according to the bible we can show if we are deserving of that gift.
Mt 7:14 talks about the cramped road and that few would be finding it. This is part of what is commonly referred to as the Sermon on the Mount. This scripture is simply saying that many people will choose to go the easy way, to do and act as they see fit, but that few would be humble and meek enough to allow Gods word to direct and guide them. Which is much more difficult than the 'popular' way. That is why just beforehand in verse 12 the 'golden rule' is mentioned. Jesus was telling his listeners that among many other things, being a true Christian would not be the easy popular course, in fact it would be difficult.
So as you mentioned these are not examples of contradictions, but they are just a guide that allows the reader to see what the bible says God does require. Because in fact all those things are required for those that choose to believe it!
As for Mt 5:17 Jesus said he came to fulfill the Law. The law he was speaking of is what is called the Mosaic Law. Gal 3:19,24,25 says what the purpose of the Law was. The law showed the people then that they could not possibly live perfect lives in harmony with what God required. Nobody could live up to all those laws. It showed that they needed that long promised 'seed' that God promised way back in the garden of eden, just after the first human sin. Jesus was that seed, he 'fulfilled' the Law. But then a new command was given. Jesus said at John 13:34 that that new law, was the law of love. Which intersetingly he stated again when he was asked what the 2 greatest commandment were! 1) love God wholeheartedly. 2) love your fellowman. Although the principles and reasons for the Mosaic Law are still the same, and according to the bible should be followed, the exact way to be done is not!
And wow, as far as the disagreement between denominations.... it is crazy. Here is an example... I may be mistaken, but I think the Hindu religion holds cows as sacred. So if I told you I was a Hindu, and a few days later you saw me at the local burger joint, scarfing down a triple cheeseburger, what would you most likely conclude? Either I do not know what a Hindu is, or I am lying, because obviously I'm not a Hindu! The same is true with Christianinty, It is not possible for them all to be right! SIMPLY PUT MANY/MOST THAT CLAIM TO BE CHRISTIAN, DENY THAT BY HOW THEY BELIEVE AND LIVE. That is why a person if they want to be Christian, cannot simply believe what somebody tells them, but it must be proven!
And according to science, the atom, of which all things are made, could not be possible without the very very fine precise tuning of the fundamental forces of nature. (strong and weak forces, nuclear, and ummm.. I dont remember the other one. lol.

) Therefore even life based on different systems, either carbon or whatever those basic elements of which the whole universe is made, couldnt exist.
And as far as other universes and aliens, I simply do not know. I dont think nobody knows. For the few things I do know, there are many more I do not! But I do know one thing, and that it is hard for me to reason there being a universe that is so well balanced, and a planet in that universe that as far as we can tell is unique, that has very very fine tuned systems, that it just happened by chance! There is just to much evidence for a designer!