I found Heroku to be a great option to get ExpressJS up and running with very little hustle. The free tier is great, but I'd recommend to set up a cronjob to visit your site every few minutes so that the server stays awake. Netlify was the option to host the front-end because doing the server side rendering on #Heroku would have taken a little more time than I'd like to. For the moment pre-rendering the app with prerender-spa-plugin is enough to help with #seo. Puppeteer was my choice over other options because it made it easier to scrape websites made on ASP.NET which is what I needed in this case. And Vue.js is my top choice at the moment because it's really beginner friendly and it has a lot of the features I like about Angular 2 and React. vuex is a must in most of the app I build.
I recommend using Travis CI and/or Appveyor in all projects.
Projects using these tools have given me confidence to know that I don't cause any breaking changes. Travis CI and Appveyor have functionality to test components of a project across multiple installation projects to ensure that modifications don't break a project. These tools integrate easily with GitHub and are useful in open source projects that must review contributions from many different people.
If jQuery or vanilla are the only two options available, then use the library that's available when its features will avoid having to reinvent wheels. Look at what jQuery offers, and look at the things you want to do. If a handmade solution doesn't require a lot of extra effort, then don't bother.
The capability of style customization is one a large deal breaker for frontend SDKs. To solve this, we decided to use styled-components in our SDK, which makes it easy to add support for themes on top of our existing components. This practice reduces the maintenance effort for stylings of custom components and keeps the overall codebase clean.
I decided to use ESLint over other tools like Prettier because I think it's better to show your fails than fix them without knowing what you are doing. It's a better way to learn. I know it's slower, but you are fully conscious of your work. I also use Sass linters for the same reason. I recommend Prettier when you are already a senior developer, but try to use linters instead when you start coding. It will help you to improve a lot. I recommend you #Airbnb rules set. Strict, but well written. Very useful even for accesibility.