I notice these commentary sets don't cover every book in the NT, only about 2/3 or so. Are these series still being completed or is that all we're going to get?
They are still being written. Projected voume author information is availble at the site Best Commentaies.
Okay great, thanks.
I'm presuming that if you already own these commentaries, the additions will not be included as they become available. If I'm wrong on that please let me know, I would be delighted.
You're not wrong. You'll need to buy the extra volumes when they're released.
Very occasionally Logos will sell an incomplete series, with new volumes then being automatically added to your library. The most obvious example is the Evangelical Exegetical Commentary. But that's made very clear before purchase.