The answer to all those questions is yes.
Conceptually the built-in web server of IS is similar to Ruby on Rails, in that you can deliver server-side processed pages.
To get started, I recommend that you look at the pages in the WmRoot
package. Using these as a starting point is what I did many years ago.
In addition, there is no problem to also use things like JQuery, Bootstrap, or even Angular. But for starters I would probably recommend to start with just Bootstrap, Tailwind, or whatever you like. And then, as always, it just depends on the requirements.
#DSP#webMethods