Okay, let's see if I can help a bit with all your questions.
1) Is node.js good for MySQL or PostgreSQL?
As far as I know, Node has a driver for both. I don't know how good the driver for MySQL is, though. A blog is simple enough that you could use either without much trouble. You could also use MongoDB, which has the advantage of storing data in object-like documents. Here it all comes down to which one you feel most comfortable with.
2) Which Template Engine should I use?
Is there any reason you don't want to use vanilla JavaScript? There are plenty of template engines and all have their merits and demerits, but they don't do anything you can't do with vanilla.
EDIT: That is not to say that you shouldn't use a template engine or that they aren't useful. I just find it easier if I don't try to use too many new things in one project. If your goal is learning a template engine, go for it, I'm sure someone can give you a much better rundown of the main ones than I can. But if your goal is to learn JavaScript, I would suggest doing it in vanilla first and then maybe trying a template engine.
How can I render my webpages with ReactJS or Angular, do I have to use a template engine like ejs and combine ejs with React or is there any different way?
You don't need to use a template engine to use React. React basically controls the state of your application and helps you separate it into components, which get updated when state changes. To render webpages with React, you just need to add it to your package.json and build it with something like webpack or parcel-builder.
3) Should I learn webpack?
It wouldn't hurt to learn. You could also go for parcel-builder, which is lighter and easier to configure. If you use React, SCSS or something like that, you'll need to use something to compile your stuff, though.
4) Should I learn Docker?
I think it's useful to have, and not particularly difficult to learn. Probably someone on DEV has written a four-minute article explaining how to use it.
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Okay, let's see if I can help a bit with all your questions.
As far as I know, Node has a driver for both. I don't know how good the driver for MySQL is, though. A blog is simple enough that you could use either without much trouble. You could also use MongoDB, which has the advantage of storing data in object-like documents. Here it all comes down to which one you feel most comfortable with.
Is there any reason you don't want to use vanilla JavaScript? There are plenty of template engines and all have their merits and demerits, but they don't do anything you can't do with vanilla.
EDIT: That is not to say that you shouldn't use a template engine or that they aren't useful. I just find it easier if I don't try to use too many new things in one project. If your goal is learning a template engine, go for it, I'm sure someone can give you a much better rundown of the main ones than I can. But if your goal is to learn JavaScript, I would suggest doing it in vanilla first and then maybe trying a template engine.
You don't need to use a template engine to use React. React basically controls the state of your application and helps you separate it into components, which get updated when state changes. To render webpages with React, you just need to add it to your package.json and build it with something like webpack or parcel-builder.
It wouldn't hurt to learn. You could also go for parcel-builder, which is lighter and easier to configure. If you use React, SCSS or something like that, you'll need to use something to compile your stuff, though.
4) Should I learn Docker?
I think it's useful to have, and not particularly difficult to learn. Probably someone on DEV has written a four-minute article explaining how to use it.