Which one?

Heinrich Zemo is an important villain in Captain America history, being the man who was responsible for Cap going into the ice (in the comics). He does have one of the most ridiculous villain origin stories ever: he hates Captain America specifically because Cap got his balaclava stuck to his face. 

His son, Helmut, is a bit of a basket case. He tried to kill Cap in disguise as the Phoenix – I would advise Jean Grey to sue, personally – and then managed to fall into a vat of the same adhesive that disfigured his dad, proving that idiocy runs in the family. Then he got married to a woman who claimed to be a reincarnation of his father, which is so bizarrely reverse-Freudian I can’t even.

I will give Helmut one thing: he’s really good at getting people to think that his villain team is actually a superhero team – because he’s done it more than once, using the exact same superhero team name. 

Overall? They’re serviceable Cap villains. Not quite as classic as the Red Skull, lacking the panache of Baron Strucker, and unlike Arnim Zola they don’t have their faces on TV screens in the middle of their robot bodies. 

This is a tricky one, because you need to start from a place of understanding Jewish subtext in film and other media, so I’m going to do a very TLDR version of this history:

Back in the 1920s and 1930s, the Hollywood studio system was dealing with a “family values” backlash, and one of the ways in which the “family values” crowd liked to bash Hollywood was to bring up the fact that a lot of the people who ran Hollywood were Jewish immigrants and were thus alien to the values of the American heartland (which of course got revived during the Cold War with the Black List and the McCarthy hearings). 

One of the ways that Hollywood dealt with this, in addition to instituting the Hays Code was to really de-emphasize Jewishness in its products. Not that Hollywood didn’t continue to make products that came out of Jewish theater – the Marx brothers, for example – they just didn’t identify characters as Jewish and used circumlocution and veiled metaphor to discuss Jewish themes. Hence, even when you could fight the caution of the studio bosses to get them to greenlight an anti-Nazi picture like Casablanca (as late as 1942!), the screenwriters and directors had to smuggle in Jewishness under the radar:

So in 1941, when Jack Kirby and Joe Simon introduced us to Captain America and the name of the scientist who gave him his powers was Professor Reinstein at a time when the most famous Jewish emigre scientist in the world was Albert Einstein, the subtext was clear: Captain America’s serum is the result of Jewish emigre science, here to save us from the threat of Nazism. And while it’s changed somewhat in the last 60-70 years, the fact that the 2011 film has Doctor Abraham Erskine be both a scientist and a quasi-rabbinical figure, the subtext is still there:

Good question!

Let me start by directing you to this essay here where I talk about how Jack Kirby and Stan Lee turned the Red Skull from a rather shaky pulp villain into a pretty damn good supervillain with a penchant for cigarette holders, giant Nazi robots, doomsday devices and improbable escapes.

They also gave him a rather interesting backstory in Tales of Suspense #66: Johann Schmidt was a penniless orphan, bullied and robbed because of his physical weakness, who couldn’t find regular employment (although as Steve Rogers points out, “my early years were no bed of roses, either”), who was working in a hotel when Hitler came into town, and the rest was destiny:

And that’s the core of the character – he is Hitler’s very own Nazi, his hand-crafted avatar of hate. But at the same time, you can see the personality defects – the self-hatred (especially centered around physical weakness), the adoration of power and strength, the “envy, the jealousy” – that would make him such an eager convert. In a way – and there’s a reason why they named him John Smith – he’s a perfect stand-in for any of “Hitler’s willing executioners.”

That’s what makes him such a good “dark mirror” for Steve Rogers – because the two of them have virtually identical backstories as poor, physically impaired orphans, but they reached such diametrically opposed ideological conclusions. Long before he volunteered for Project Rebirth, Steve Rogers had chosen the path of solidarity, and before Johann Schmidt got his mask/face, he chose the opposite. Hence why this moment works so well:

The Red Skull needs there to be some inherent, almost biological reason, why Steve Rogers succeeded where he failed, because otherwise he has no way of understanding his life. And it’s a big part of the reason why so many of his plans revolve around trying to break down Captain America – drive him crazy, take over his body, putting NYC in a bubble unless Cap gives in – to find that reason and overcome it. 

That being said, one major mistake I think people make with the Red Skull is that they try to make him too smart (he’s not a Batman-level strategic genius – he’s a monologuer, a gloater, a fan of the easily-escaped-death-trap and the explosion-prone-giant-robot) or too powerful (the Cosmic Cube should always be something he’s reaching for, but which always slips between his fingers).