Well, you are asking difficult questions! I'm kind of weak with Greek conditional sentences. For me this seems natural, but I don't know why - it's just that I'm more familiar with Homeric Greek than with Attic. Other people will probably be able to articulate an answer and then I will learn something new too...
The Basel "Gesammtkommentar" has a word to say about κεν αὐτὸς ἕλωμαι: "Agamemnon betont seine Autonomie [...], formuliert die Drohung aber etwas vage: Der prospektive Konj. (im Hauptsatz fast nur bei Homer: SCHW. 2.310f.) ist Ausdruck einer subjektiven Erwartung, etwa: 'dann sollte ich mir wohl selbst nehmen'."
I suppose this is a sort of answer to your second question. SCHW. refers to a Greek grammar by Schwützer, Debrünner, Georgacas and Radt. I have never seen that book, perhaps you have access to that? (unfortunately the don't refer to Chantraine here, since the commentary is aimed at German speakers)
If that's the sort of thing you are asking, you'll have to get your Chantraine vol 2 pretty soon! (I didn't have the time to look there yet myself)
Ah, indeed - the Basel Gesammtkommentar
are recent (rather expensive) commentaries in German on individual books of the Iliad. Since you are familiar with German, they are an alternative to the Oxford/Cambridge commentaries. So, if you still insist on getting more books, you might consider them... For each book that has a commentary, there is one volume with the Greek text (West's edition) + a translation and another volume with the commentary.