Interesting. Edea's speech in particular is quite a change from the original (though I'm not sure just how much closer to the original a Korean guide would be). It's a bit more grounded in reality. The original is all a bit too vague for the player at that point of the game, because they know nothing about Ultimecia and Time Compression at that point. So I guess at least the English version sets the tone a bit better, and firmly sets Edea as the enemy.

The second scenario is just plain wrong, but it doesn't affect the game at all, other than maybe making the player think that Seifer may come back into the picture later on.

I don't see any difference between the original and English translation in the first scenario. I don't think 'asking him for advice' necessarily implies that Seifer went over to Timber and actively participated in the rebellion. They could've just been talking over the phone.