Plot holes in Zemo's plan in Captain America : Civil War [closed]

That's a lot of questions, but the all have basically the same answer: Zemo's plan was both well-research and fluid, so he could adapt what he knew to changing circumstances to get what he wanted.

To start with, Zemo knew a whole lot about HYDRA and the Winter Soldier programs before he even began. He learned all of this from reading the data dump Natasha put on the Internet at the end of Captain America: The Winter Soldier. From this, he learned, among other things:

• About the existence of the Winter Soldier program, and
• About a key incident that occurred in 1991, and
• That HYDRA was responsible for, among other things, the murder of Howard Stark.

We already knew the details of Stark's murder were in HYDRA's files, because Armin Zola told Steve Rogers about them earlier in that same movie. It makes perfect sense that the Winter Soldier program's records were there, too, since Zola was using HYDRA-with-SHIELD to run that program.

It's not 100% clear why Zemo was unable to find the location of the base in all of these records, but maybe Zola managed to delete it, or encrypt it somehow that couldn't be broken, or whatever. Zemo knew it was somewhere, he just needed to find it. On his first attempt, he didn't locate the base but he did locate Barnes's codebook, so he adapted to his new plan. The fact that the Avengers were in Vienna, as opposed to NYC or Paris, or wherever, was irrelevant. He just wanted to make them drive Bucky out into the open for him and secure him somewhere.

Once that was done, he had access to the intel he needed. I'm not sure why you'd assume a bunch of people who happened to be at the UN offices in Vienna would know the faces of every single other UN employee on sight. Zemo had the proper credentials so he was allowed into the building. It's also not unusual for prisoners to be interrogated alone, on the presumption that they're secured and under surveillance at all times.

The fact that he ultimately confronted Tony and Steve in the base at the end may have been part of his plan, or it may have been a happy accident. He went there to retrieve the video tape, but there's nothing that says he had to show it to Tony there. He saw an opportunity to bring Cap and Tony to him by tipping them off, but if that hadn't worked out, he had the video. He could have sent it to Tony at any time in the future and had a similar effect.

None of these are plot holes. The things that seem convenient or unlikely are either the result of 1) very careful planning, or 2) Zemo adapting his plan to match the circumstances he found himself in.