Populist is different from using xenophobia and racism to scape goat certain groups and buoy yourself to popularity. In that sense Trump is very much taking a page out of Hitler's play book, however in the long run that will blow up in his face.

Depends on what you put the blame on and how you do it. I havn't followed Bernie Sanders, so I don't know much about him. But looking at certain topics about him, he was also labeled as a populist.

This is a good read:

https://www.theguardian.com/books/2016/sep/02/trump-erdogan-farage-the-attractions-of-populism-for-politicians-the-dangers-for-democracy

Doesn't need an expert for this.
There already are lots of people comparing them, or better: USA to past Germany. Build a wall, own nation first, fake news, nice hair, actual actions and not just political talk, appealing to the "lower" masses that grew sick of their lives. It may be comedy but it's true.

With ease? Less than a month into his first term and he's already causing national and international outrage while promoting an almost Orwellian view of the free press a.k.a fake news...

Within two years he'll be impeached and the Republicans will happily put Pence in charge. I have a feeling that parts of Trumps inner-circle are setting him up for a fall to enable this - it's hard to see why he hasn't been told to leave the idea of fake news alone, or election fraud, other than certain people want to see him fail.

Reading this is showing how the generation today have no clue of what really happened in Germany after the first world war and are just using words or historical events without really understanding the meaning of it. And the worse part is that is exactly what a lot of anti-Trump are using to descibe him... 
This is also bad because, someone like me who would never support or vote for Trump, can see how wrong the other side is too and how they are doing exactly the same thing... Trump may be using fear of terrosism and other things... But using Hitler and stuff like to defend your point that is as wrong and out of place... a LOT of people died because of Hitler and how bad it was back then; be respectful and stop comparing what is going on right now which is really nothing compared to that.

So let's go with your points:

Build a wall
Really? Do you even have a slight understanding of what was this wall in Germany and the purpose on it? My guess is not; or you would not even dare to compare it to the wall Trump is talking about... Those are 2 completly different things. Having both concepts using the word "wall" does not imply they have the same purpose at all.

Own Nation First and Taking action instead of just talk
In what country are you living? Because I do not know any country, not trying to put their own interrests first (or interrest of their citizens)... This is quite the basics. Same goes for the taking action instead of just talking. The majority of elected politicians are actually trying to take actions (like Trump) whenever they can (hell, even the joke J. Trudeau in Canada is doing that... Not going to compare him or the country to Hitler or Germany after the first world war based on that...). 

Appealing to the lower masses -> 
"Lower" masses?
- First of all, even if you are talking about half of the USA (who voted for Trump) when you are referring to those "lower" masses, it is obviously wrong. My hope is that you are doing this and not trying to classify this half as inferior as the other which would be even worse.  
- Second, this is EXACTLY what you are doing (or this article): using names like "Hitler" to try to get people to believe how horrific Trump is...

Not even going to talk about the "Nice Hair" and other killing comparison there....

Agreed. It's extremely disrespectful to the people who died in this horrific event to pretend this is even the same and I've been saying that for a long time. It reminds me of people who say "this is the worst time in America". Yea except for the time we enslaved a whole race of people and wiped out the indians but keep downplaying those horrific events because of your first world problems. 

I get not liking Trump but people need to calm down and start approaching this way more logically and stop with the exaggerations and the dramatics. I have people on my FB saying stupid stuff like "I'm so scared right now". I have an older cousin who I respect who saying stupid stuff like this and I lost a bit of respect for her. She of all people should know better. Not even going to get into how she dismisses any and all negative aspects concerning Hillary.

Whether or not he's Hitler, I'm sure that doesn't matter much to Syrian families getting bombed by the United States.

They have to be at least somewhat comparable.

Looking at Trump's twitter feed, I'd say he has more in common with your average teenage girl.