I think most of the issues I found are due to your wish to get down the plot and finish the first draft. But while I do get that impatience, you should take care not to overdo it. In this chapter, it seemed very much as though the plot were driving the characters, to the point that they were all rather flat and - in parts - unrealistic.
Garrik, for instance, is overly emotional, going from anger to tears and back within a few seconds, with no transition being apparent. Which would be fine, if that were a constant state. However, he then is perfectly content to let Vardis tell him everything in his own time. What I'm getting at is that if the characters were in fact driving the plot, that whole scene might have gone into an entirely different direction, so you might want to reign in the impatience a bit.
In contrast, the "infodump" (which it wasn't, really) about the Will and such was very nicely done. It fitted in perfectly, and felt as if it was something that had to be said, not something the author felt the reader should probably know at this point. I think you're handling setting and such quite well overall, first draft or no.
You should consider making the part where Garrik controls the will slightly shorter. By the time your buildup to the branch snapping is done (and the branch snaps), it's quite obvious what will happen, and Vardis' explanation on top of that is fairly unnecessary. So maybe lose one of the sentences describing Garrik's anger and let him realise on his own what Vardis did. You're probably going to completely change that when rewriting anyway, I know, it's just such a pivotal scene that I thought I should point it out.
And to end with a minor issue, you should probably reword the description of how the necklace works. As is, one might think that it conceals Garrik's eyes from everyone but himself, which would make him quite dense for not realising the implications somewhat earlier.
The additional scene you propose sounds good, I'd recommend you put Vardis in it. That way you could better establish that everyone trusts him. Otherwise their letting him wander off with the heir to train him would have appeared somewhat reckless.^^