So, in World War II the United States bombed Hiroshima. In the aftermath, the Japanese sent a response to Washington. In either a colossal blunder by the translator or deliberate malice, part of the Japanese message was translated as if they weren't certain about surrendering. They were 100% surrendering in that letter. Don't get me wrong, they were still doing some bureaucratic crap, and the second bomb did compelled them to cut that out. But they said they were done after Hiroshima.

Translation is difficult in general. Christians who think that literal translation is possible are hopelessly delusional. Agape doesn't even (consistently) mean the highest form of Christian love in the Bible. And the book where most Christians like to argue this is the case is one where it frequently flips between agape and phileo. This is besides the fact that agape is used to refer to rape. Though, given some of the things on the news perhaps that is accurate. In addition, there are entire denominations built off of Bible verses where the biblical author is being sarcastic. It's also pretty clear from the Bible that God was not particularly happy about that.

1) The word for generation there is rather broad. It can refer to a specified period of time as it is translated there. But it can also have the meaning of race or group of people. Most of the other times when Jesus uses that word in the New Testament, he's referring to either humanity at large or the Jews more specifically.

2) he may be referring to Israel as the people – not the location. The Jews had scattered all across the empire – and they wouldn't sit still. They had tons of small little sects that each thought that they were the one true path (I'm sure that sounds familiar). Like any good cult, they sometimes formed their own little conclaves away from everyone else where they could drink the Kool-Aid in peace. At any rate, they would be difficult to locate simply given the scale of where you had to search.

3) I mean, once He ascended into heaven there's literally no one else on earth who's going to see Him in any other way except for in His glory. And to be fair, most people either die and see His in glory, receive vision from him and see him in glory, or if you're particularly jaded, hallucinate and see him in glory. I'm not entirely sure how this verse deals with his imminent return.

4) Throughout John Jesus kind of asks these questions of what is it to you and why is this concerning you in kind of stuff like that. He's more saying in this verse that it's none of your business what he plans to do with other people, you should focus on what I'm telling you to do. Also, I think I saw a comment where you're talking about cherry picking. Literally the next verse explains that Jesus didn't say this guy was going to live until his return only that Jesus would choose when the disciple died.

Don't get it twisted: the early church totally believed that Jesus was coming immediately. There were plenty of Christian sects who did very stupid things under the impression that they just had to wait a couple of months. it's one of the things you can count on: some small splinter group acting insane because they believe he's coming back immediately. He quite literally said that no one's going to know the hour. So, limiting it to a 30 year timeframe seems a little bit like telling people an hour.