Negative in a question with various negative valence words

You need to disambiguate the word there. In sentence c. it is an adverb of place, whereas in all the other sentences it is the dummy subject. In fact, my native-speaker ears find sentences with both theres better. My preference would be for:

• a) Why isn't there ever anyone there?

or, best of all:

• b) Why is there never anyone there?

Sentence c. also sounds ok:

• c) Why is no one ever there?

c) Why is no one ever there? is a good choice. You could also say:

g) Why isn't anyone ever there?

C1) Is a double negative and makes you sound uneducated (white trash) and e) just sounds weird (and it is also a double negative).

a, b, c, d, and f are acceptable, but i think the best ones to use would be a, b, and f.

(I would ask "Why isn't anyone ever there?")

I understand your puzzlement; I recall how strange it was at first to use kein and to give up the idea of using Negative Polarity "any" in German.

Of the sentences above, only (c₁) and (e) are ungrammatical -- both, as BillyNair points out, because they use two overt negatives that don't cancel out: never and no one in (c₁), and isn't and no one in (e). The others have only one negative apiece, since any is not negative itself, but rather a Negative Polarity Item that can occur only with a Negative Trigger. Negation is a complicated subject.

And as Shoe points out, there are several types of there there. The ones you can substitute here for grammatically are the ones that occur at the end of the clause, generally. There are exceptions, of course. There-Insertion is also complicated.

Most of the sentences you proposed are technically correct. A few aren't, due to a double negative that causes the meaning to change. Of those that are correct, I would say that the most natural sounding is:

b: Why is there never anyone (here)?

Another natural sounding choice would be:

a: Why isn't there ever anyone (here)?

meaning literally the same as b. Using never instead of not ever flows more smoothly, however, and I think it would be the better choice in most cases. In both cases, adding the word "here", while not necessary, helps specify where you are talking about.

The others are all valid, with the following exceptions:

c1: Why is there never no-one?

e: Why isn't there no-one ever?

Using never no-one is a double negative, which reverses the original meaning of the phrase.

Likewise, isn't no-one literally means is not no-one (If no one isn't there, somebody must be!)