Is Ruby on Rails really a candidate for bare minimum? Part of the reason I backed off was the enormity of Rails. Part of why I'm doing this is to understand what's going on under the covers and Rails feels like it has a broader and more opaque cover than most other options.
With scaffolding, you can have a functioning Rails CRUD app in literally minutes. There is a lot of stuff Rails _can_ do, but not a lot of stuff you _need_ to do. You don’t even need to write a single line of JavaScript if you don’t want to.
rails new && rails g scaffold Movies title:string && rake db:migrate && rails s
Visit localhost:3000 in your browser and there you go.
With that short line, you can CRUD Movies including a functional UI.
Obviously “real” apps will require a bit more work, but not much depending on how complex you need things to be. The Rails Guides are super helpful.
If someone wants a more robust and production-ready intro to Rails, Michael Hartl’s free Rails Tutorial is exceptionally good.
I only mentioned it because you said you did some research/learning on it. Seems like the best choice from all the technologies you listed because it is the more mature for web development.
Other than that, no it isn't necessary. You could start with plain HTML and JavaScript only. But sooner or later you'll have to choose one tech for backend.
