I just found this thread right after I posted:
http://www.orthodoxchristianity.net/forum/index.php/topic,4996.0.html
It answers some of the questions, but not all of them. For instance...
What I heard was that St. Severus is still anathematized by the Armenian church even after the joint 726 council. Why would this be, if it is indeed true?
Welcome to the forum.
If you click on the tags below, you'll find other threads discussing St. Severus, but I'll answer what I can here.
St. Severus is not still anathematized by the Armenian Church. He is not on our calendar, but I've been told that we Armenians are free to venerate him, like so many other saints of our brother OO Churches who may not be on our calendar, but whom we can venerate. In fact, Father VC Samuel confirms in his book
The Council of Chalcedon Re-Examined that St. Severus was considered a saint in our Church after 726. (page 168)
Also, it was mentioned that there were some teachings associated with Severus or possibly even from Severus himself that were supposedly condemned by this council. What are those teachings? Did Severus really teach them? And is there actually substance behind the claim that Severus tolerated the phrase "in two natures" ever?
I'm not sure which teachings of St. Severus to which you are referring. We condemned Julianism and accepted the teachings of St. Severus at that council.
I have never heard about St. Severus using the phrase "in two natures." It has probably been discussed or debated here, but I can't recall.
I need to let you know that debates about Chalcedon on OCnet now take place in a private forum, to which you need to ask admission. We've done that because such debates can get nasty.

The most thorough discussions about St. Severus have probably taken place there. If you want admission to the private forums, you just need to pm Fr. Chris and ask.