Quite frankly, I'm of the opinion that you are guilty of adultery if you remarry for reasons other than Yeshua specified.
I don't think that sin "rests" on you, unless you willfully ignored the spirit on that particular issue and are living in a state of spiritual rebellion.
To say that when both parties remarried and die remarried to their second wives/husbands that they die living in the sin of adultery is a stretch is all I can say. I'm not saying it isn't completely erroneous when factoring in law-based grace (which is something that some practice) but I would imagine that someone that had a legal mind about such things wouldn't do it in the first place.
That's up to each individual but the word is clear on homosexuality as it is with sexual immorality about who will not inherit. I take those verses to mean living in willful rebellion (sin). Like knowing that the Lord was against your marriage and marrying anyway...feeling the conviction (tested, and not just a guilty conscience as far as you can) and simply ignoring it. Personally, I understand that we want things to be clearer and clearer, feeling more conviction heaped on us in order to know for sure that it isn't just a guilty conscience or human judgement, but in my own personal experience, this is quite rare...Especially when plain text is ignored.
As an aside, if you only consider the direct words of Jesus that are red-lettered as something to follow and throw out what the Old testament says about these issues then you need to do a deeper study of what "the word" (john 1:1 ctd) means.
OT, there was an "allowance" for divorce as there was an allowance for polygamy. That doesn't mean that was the Lord's preference, but sort of a "reap what you sow" sort of thing. It was not vague on the issue you are trying to say is alright and you should be accepted in the church because of. It is weakness to ignore a clear leading/command because you cannot submit to the Lord in physical areas. We all have weaknesses however, and workarounds/hotfixes have their place.
You are forgetting that Jesus made a further distinction about adultery regarding simply thinking lustfully about a woman. Based off that, most all of us are guilty by default.
I also find it strange that you are using the adulterous remarriage argument (and calling it sin), and are suggesting that while you are sinning, it isn't that bad, and that you should simply be allowed to have this sin overlooked by the church because everyone else's is and they are similar enough.
If only the catholics had it right, that they could absolve me from my sin. But the priest said I'm good. I'm accepted into this community of "believers" and my sinful lifestyle is accepted and I have no desire to change but I love the Lord and I love who I am with, so it's all good...that other stuff is so "old testament".
Personally dude, I'd run away from a church like that. It's not about what the lukewarm church thinks about things...in my view, most of them have a 50/50 shot of inheriting. You would do well to find a solid church and at least tell them you are open to the fact that you are living in willful rebellion, but the conviction is not there (a presumption on my part and I pray that changes), and as a result...you are open to prayer for that, you are willing to lay your relationship and your orientation on the cross (I.e crucify it), but that you are having a hard time doing so, because it feels correct to you. You just want to be happy, regardless of whether happiness is scriptural or not (Joy is, but happiness you would have a hard time proving scripturally).
I'm not unaware personally of forbidden sexual attractions. Having been tempted with many things, you at least have to accede to the fact that the energy is different. It is possible that focusing on the differences and bringing it before the Lord, he may be willing to guide you through it in a way that is rare. I don't mean practically, I mean experientially through the past. I've had certain things from my childhood brought up that hearken to traps I've fallen into as an adult and memory recall/triggers I attribute to him, as well as the interpretation thereof.
Note: everything I have just propounded is based on adherence to scripture. If a person has no interest in that, my responses would be different.
I just find it interesting that people will reinterpret that clear words of scripture for marriage in the modern age in a way they won't for homosexuality.