Are you implying that the two pronunciations are the same? Because there's still a subtle difference to be detected between جاكيت (jaakiit) and جاكِيَت (jaakiet), the later being a wrong pronunciation that needs to be reported and replaced with the former.

Yes, I hear jaakiet too

I don't think there can be, because that yaa' is acting as a vowel (ii) rather than a consonant (y) here, so it can't take a diacritic. (In my beginner's understanding, anyway.)

You're right. It's being pronounced wrongly, the right pronunciation being jaakiit. The best thing to do is report this error whenever we come across it.

Depending on the region the "j" can sound soft like in "bonjour", somewhat hard like "jungle", or hard like a "g" as in "great".

Wrong, there's many ways to pronounce ج. j like jungle in some places. j like French bonjour. g like "good" in Egypt. And even in Sudan they pronounce it almost like a "y" sound mixed with an English "j" sound.

There's many different ways to pronounce ج

you are right, it does NOT depend on dialectical, this is why MSA is standardized. If by dialectical, in Egypt it is pronounced entirely differently for instance.

In MSA there is only one pronunciation for ج and it is the 'j' as in jacket or the 'g' as in giraffe.

It depends on which country and region you're from. It can be said either way.