Absolutely!
React:
React is necessary because when you're using a non-React library, you have a ton of code all over the place that updates the view. Example. Say you have up and down buttons for adjusting brightness. In both of those buttons you'd have to do $('brightness-div').adjustBrightness(newValue). Not so bad. Oh wait, you also have a button which automatically sets the brightness somewhere else, so you need more for that guy too: $('brightness-div').adjustBrightness(getAutomaticValue()).
This is OK, but now what if you want to not only adjust the brightness-div, but also the brightness-span whenever the brightness changes? You now have to hunt through your code in n different places to update the code. That sucks. Much better is the React way, which would replace all the direct div access with an update of a shared model. Now you'd just go this.model.brightness = newValue in each of the 3 places. Then in the render() function, which gets called when the model changes, you'd set the brightness of your div appropriately. And when the DOM changes and you need to update more elements, all you have to do is update the render() method to set the brightness of the span as well.
Redux:
Redux solves the problem of deeply nested dependencies. Say you have a bunch of nested objects in your project - your App has a Menu Bar, which has a Menu Item, which has a Label. Now, the App has the filename, but the Label needs it, because it's a Save "Filename" label. The traditional way would be to pass down the file name from App to Menu Bar to Menu Item to Label, which works, but it's kinda crappy. You have to update 4 classes just to pass some data around. And if you want to refactor your Menu Bar, or move the Label somewhere else, you have to remember to pass the data a different way now.
The best way to understand Redux is that it gives you a giant global variable of all the state in your app. ALL OF IT. Then you can slice it up and each component can take only the pieces it need. Now Label can simply tap into the global variable, grab the file name, and be done. (It also gives you some regimented ways of updating the global variable in such a way that everything doesn't descend into insanity, like stuff sometimes does with global variables.)
This is why a lot of people don't get Redux - they don't have deeply nested dependencies, so it doesn't really change their code in any way, except to add boilerplate. But if you have reached the size where you do, it's a life changer. Seriously.
Immutable.js:
This one's easy - and yet curiously I've never seen my explanation for why immutability is necessary anywhere. People always start talking about data races and concurrency, which never make any sense to me because if you have a sequencing problem with mutable data, you're gonna have the same sequencing problem with immutable data. Immutable data is not a panacea! But I digress. Let me get to the explanation.
Say you have a HashSet of Points. You put point1, point2, and point3 into the HashSet. Now, you say var p = Set.getFirstPoint() and then do p.x += 5. Does your HashSet contain p now? It's a trick question! Sets do comparisons by comparing hashes, and they do the hashing when you insert the point into the HashSet. The HashSet can't possibly know that the hash value of your point has changed, because you haven't touched the HashSet at all, just the point inside it. Even if it could, expecting a harmless line of code like "p.x += 5" to go off and update a bunch of HashSets intuitively feels insane!
What does this have to do with immutability? Well, look what happens if Point is immutable. Now you can't just go and mutate your point directly to change it's position in the Set - you'd have to remove it from the HashSet, and add a new one. Now the HashSet knows that you changed its contents, because you removed and added a point. So the hashes are always consistent.
Obviously immutability isn't just necessary for keeping hashmaps consistent, but hopefully this allows you to see how immutable data allows you to write data structures that don't get out of sync with each other. It eliminates some ways for that "out-of-sync"-ness to happen.
Webpack:
This one's the easiest of all. Eventually, you're going to need modules. So, you install Webpack. THE END. :D I avoided Webpack for a long time because the webpage makes it look hard to use, but it's actually very straightforward once you click through about 6 pages of why Webpack is the best thing ever. (Sigh.)
---
I hope that all is helpful in some way!