1 It's "sou ja nakute", naku is how nai flips over before te. The long o must be your problem. It's a VERY common phrase, heard in almost every series. The "sou ja nakute nai, desyo" sounds like garbage though. I'll recheck ep.10 maybe in a few hours.

Kekkou means "good", basically. My dictionary says "good, fine, nice". It's a na-type adjitive.

2

I do still have a lot of trouble hearing lengthened vowels, but that wasn't the problem for the first one. The problem was that I didn't know that about "naku" and it doesn't appear in the dictionary I've been using.

I don't understand why I couldn't find "kekkou". I searched for "kekko" and I don't remember it turning anything up -- but I just tried it again, and "kekkou" was one of the first hits. Rats.

Thanks for your help!

3 BTW, I talked this over with Ana-sempai and she reminded me that the -te is the junctional, e.g. you can say "sou ja nai. betsuni yo." in two separate sentences, or join them with the -te, "sou ja nakute, betsuni yo". I tend to do this in English too, just look how long the previous sentence was. Ergo, "sou ja nakute..." means that something else is meant to follow (although in most cases it does not in fact follow). The English equivalent of it is an ellipse, I suppose.

4

It's not uncommon for them to leave things out, even to the point of not making any sense. Consider nandemo nai for example; literally it means "everything not" and colloquially it means "never mind" or "it was nothing".

Sometimes a character will say nandemo and leave off the nai negate, in which case it literally means "everything", which the person still means "it was nothing".

So it's not too surprising to see a junctional as the end of a sentence without anything following it. That's the kind of thing that happens in living languages.