JW’s (like most religions) believe that their religion is the only true religion. So there isn’t a belief that other people could make it to heaven if that makes sense.
I’ll give an example to try and answer your question. Many Christians believe that when they die, they go to heaven or hell. However, JW’s don’t believe in hell and the goal isn’t to get to heaven. Only some (144,000 which have been chosen) will make it to heaven. Heaven is where you’ll sit with Jesus Christ and the angels once if you’ve made it there.
The goal for most ordinary people is that you’ll make it to paradise. Paradise is what happens after armageddon. It’s when all unbelievers will die and the world will be perfect (like when Adam & Eve lived in a perfect world). I hope that makes sense.
JWs can marry outside of their religion however it is discouraged. I have 3 friends who are all siblings. There mum is baptised and married to a non JW (their dad). 2 of my friends are baptised but the third friend isn’t. The reason why marrying outside of the religion is discouraged is because there’s a belief that it can bring some conflict. I remember a girl in the congregation who had an abusive dad (non beliver). Her dad would always verbally abuse her and her mum if they left to go to a meeting. No one can stop a JW marrying someone who isn’t though. It’s the individuals choice.
Abortion isn’t something that is ‘accepted.’ That’s another thing I never agreed with. It’s considered a sin to have an abortion.
Good question regarding contraception. Anyone can use contraception but it depends on the reasoning. Say you’re married then you can use contraception. Say you’re unmarried and wanting to use contraception to practice safe sex. That wouldn’t be allowed because sex outside of marriage isn’t allowed. Say you’re using contraception because you have painful periods or something like that, that would be fine.
Really and truly, no one knows what anyone is doing. Someone can be baptised, using contraception and having sex outside of marriage. No one would know unless they spoke to an elder to inform them of their ‘sin.’ Otherwise it’s really just between them and God. Hope that all makes sense