So what are the logistics of a Stormcloak (having completed the Civil War) helping the East Empire Company? What about a Stormcloak who also assassinated the emperor? The reason I ask this here is, I've heard (but haven't actually seen for myself) that the EEC makes some sort of appearance in Dragonborn; I just want to figure out how well a Stormcloak would fit in here and whether he/she would opt to help them or participate in whatever's going on. Just planning out my characters for when this comes out on PC.

The EEC is sponsored by the Empire, but not under direct control of them. So essentially its just a merchant/shipping company being used by who ever is in charge. Affiliation would honestly have little impact of them, as long as they have a business they can run.

In regards to the EEC in the DB, there is no presence, you're simply sent on a treasure hunt to find items, being paid in gold per turned in.

I believe the EEC first appears in Morrowind. There it is a company created by the Emperor, run by a board of people he appoints directly. Basically it was a private corporation owned by the Emperor. Its purpose was to exploit the unique goods that Morrowind had to offer, things like kwama eggs, saltrice, dwemer artifacts, raw ebony and glass, etc... They were the only company allowed to trade in these goods. If you walked into an ebony or glass mine the guards would tell you that the ore is the personal property of the Emperor, and that if you touch one piece they will kill you.

However, that was 200 years ago, and a lot changed since then. The Septims are gone, Vvardenfell was turned into a smoking crater, and mainland Morrowind conquered by the Argonians (though they later withdrew their troops). All of these things would have crippled the EEC's operations at that time. We do not know what is happening in Morrowind now. It does not appear that there is an Imperial presence there anymore. I have only seen it said that the Empire consists of Cyrodiil, High Rock, and Skyrim. So it looks like the Imps never went back. There is probably not much worth going back for anymore.

Since the EEC is still around, it must have adapted quite a bit to the new situation. With Morrowind a ruin, they must be trading in goods from other places now. It would seem reasonable that over the last two centuries they have morphed into an ordinary import/export company. Given that after a Stormcloak victory the EEC is still allowed to freely go about its business - and even during the war it is not bothered by the 'Cloaks - it seems likely that the Emperor no longer personally owns it. My guess would be that it is now a public company that just happens to be headquartered in Cyrodiil, that trades wherever it can find a profit.

If the latter is the case, then it is just a matter of getting involved with a company that is based in Cyrodiil. If you have finished the Civil War, it would be like an American doing work for Mitsubishi in 1946, or a German working for General Motors. If you have not finished it, well that would be just like Northern merchants trading with Southern ones during the U.S. Civil War. It was not supposed to happen, but it did on the sly.

If the East empire company was Imperial related in current times they would have been kicked out of Windhelm ages when the Rebellion began.

They bring coin for the Stormcloaks/Windhelm, so its very possible that they would help them.

The Empire is just one of their sponsors.

Granted the Empire is one of their biggest sponsors...obviously.

They don't have a giant role regardless...

east empire company ? a great potential almost throwed away

Would have been great if a merchants guild of some type was tied to them, could have been a nice addition to a thief type character.

I see it as an Elder Scroll equivalent to the British East India Company. In the early days, it served the crown. But then on it's own, it got huge and became a power of it's own.

I think when you reopen the mines, they reestablish contact with Raven Rock, but we never see them in-game. They're just mentioned in dialog.

This has virtually no real negative repercussions with the Stormcloaks. They trade with them as well.