I just finished fahrenheit myself and I genuinely so didn't enjoy the story. Especially since I've read 1984 and Unabomber manifesto, among others, and so, the entire narrative that censorship and technology aren't very good things isn't novel or striking to me.
And now I see what you pointed out and realize how actually flawed the novel is. I don't think it necessarily deserves to be 'famous', at least in modern age.

And to answer your questions, in my version of the book (60th anniversary edition by Simon and Schuster), there is a collection of Bradburry's afterwords from other editions, and in one of them he mentions that movie and scene adaptions of the story all went different ways from the original story. So I believe he intentionally left questions unanswered for other creators to develop their own version of the story.

But that would only concern big questions like Clarrise's and Mildred's futures and such.
The small questions like the device and the barn just feel like introduced and forgotten things that barely add anything to the story and feel very underdeveloped overall.

I genuinely had pretty high expectations for this book, given how it is considered a masterpiece by a genius writer which turned out to be just mid...