The many ways to request something from someone else

Question

From what I gathered, there are many ways to request something of someone. For example, consider:
1.　伝えてくれませんか
2.　伝えてくれれば助かります (This sounds like if you relay (the message), I will be saved, but my colleagues told me it's more like saying thanks, so its real translation is I will be thankful if you relay the message)
3.　伝えてくれれば感謝します (This sounds exactly like sentence 2, but I have never heard it before for some reason)
4.　伝えて欲しいなぁ (This sounds like I am forcing someone to do something)
5.　伝えてください (Translates to please relay the message, but sounds like I am forcing again, such that he doesn't have a choice)
6.　伝えてくれるといい

So now the question is, under which circumstances should I say each sentence? I'm looking for a semi casual-ish style (to put it in a fashion sense, almost like a man wearing a polo shirt and jeans to work instead of a full body suit), and also one that doesn't give the impression that I am forcing someone to do something (like in sentence 4 and 5).

Answer 1

１。伝えてくれませんか。→ Formally works everywhere.

２。伝えてくれれば助かります。→ To say formally but more like "It will be nice if you relay the message". I think you already explained it nicely.

３。伝えてくれれば感謝します。→ Yes, this is exactly like 2., but more in "asking" attitude. I would say "It will be very nice if you relay the message". Of course the direct translation is "I will thank you if you relay the message", but this is not a good translation.

４。伝えて欲しいな。→ This is more informal and not really asking. (not forcing, of course) Direct translation is : "I wish he(but actually he is the one who you are talking to) relay the message". So it just specifies the wish, not really asking. Of course this is often used when two speakers are close each other, and can be rude if you are in formal relationship.

５。伝えてください。→ Also formally works, but compare to 1., this is when you have the rules to control. And yes, as you said, it can sound more forcing, so people use often 1..

６。伝えてくれるといい。→ This is mostly used when you are superior to other in terms of 先輩（せんぱい）、先生（せんせい）,etc. Directly, it is not asking anything, but of course you are asking something to the listener. You can use this to your close friends or coworkers as well, but not to someone who you just met in formal place.