Talking about contextual things... Which Pronouns to use?

Question

Apologies is this is an easy to answer or hard to explain question...
In English we often use demonstrative pronouns to reference what we just talked about.

For example:
The busiest stations in the world are in Japan. Such as Shinjuku, Shibuya, or Umeda. Everyday, millions of people use these stations.

Now I've always had issues with trying this in Japanese.
世界に一番忙しい駅は日本にあります。例えば、しんじゅく駅やしぶや駅やうめだ駅です。毎日、数百万の人は「何々」を使います。

Initially, I feel like I would just drop the は and just do 毎日、数百万の人が使います。Is this the only way to get the same meaning?

Answer 1

The most natural phrase choices there would include:

「これらの駅{えき}」 or 「これらの[3駅]{さんえき}」.

This might surprise you, but quite a few native speakers would aslo use:

「この3駅」

which is also a very natural phrase for us natve speakers.

What you would rarely see/hear us use in this particular context is just the pronoun 「これら」.

Finally, this has nothing to do with your question, but you need to say 「世界で一番」 instead of 「世界に一番」.

And it is 「数百万の人が」 and not 「数百万の人は」.

Initially, I feel like I would just drop the は and just do 毎日、数百万の人が使います。Is this the only way to get the same meaning?

That is actually a good idea. It would even be better if you used the emphatic 「もの」 instead of the plain 「の」 and said 「数百万人もの人（or 人々）」.