I don't know when the next sale is. There may be one in the fall, but it's too early to know. There are some miscellaneous tutorials on the Garritan Wiki (link below). It seems that they are a bit hidden... in that you have to scroll down to the bottom of the page, where you will find "Miscellaneous Tutorials":
All of the tutorials that you mentioned used to be on the site are for Kontakt. They were removed to avoid confusion, as many of them need to be converted to ARIA.
We will have a tutorial contest soon where users can write tutorials and maybe win prizes. First, some things with COMB need to be sorted out. Once that is done, all the libraries will be in ARIA and shortly after the tutorial contest will follow.