[Grammar] He's coming in 5 minutes.

[Aivi5]

Hello. I would like to know the main difference between "he's coming in 5 minutes" and "he will be here in 5 minutes."
I've been told once that when I use the "nearing future" words I can use them with present progressive as well as with future simple, but I need a short and brief explanation about when and how to use exactly.
Another example, "i will fly to Japan next week" and "I'm flying to Japan next week."
I would really like to know how to differentiate between the two since I'm having trouble doing so.

2. I would also like to know if its possible to use past perfect simple when you don't necessarily have past simple in your sentence? For example:
"they deserve to win that trophy after they had been eliminated"

 

[teechar]

Hello. I would like to know the main difference between "he's coming in 5 minutes" and "he will be here in 5 minutes."

There's effectively no difference in meaning.

I've been told once that when I use the "nearing future" words I can use them with present progressive as well as with future simple, but I need a short and brief explanation about when and how to use exactly.

This is a QTND (question that never dies), and unfortunately, there is no clear answer or foolproof rules for differentiating the use of those two structures. The usual answer you get is that the future simple indicates intention while the present progressive indicates more-concrete plans and arrangements. However, please note that there is much overlap in their use.

Another example, "I will fly to Japan next week" and "I'm flying to Japan next week."
I would really like to know how to differentiate between the two since I'm having trouble doing so.

See above.

2. I would also like to know if it's possible to use past perfect simple when you don't necessarily have past simple in your sentence. For example:
"they deserve to win that trophy after they had been eliminated"

I don't understand what you mean by that. Actually, I asked you before not to post multiple questions in the same thread. So please start a new thread for this second question. Let's keep this discussion about the first question only.