[@Crusader Lord]
Your Master is mostly alright as well. However, there are a few minor issues here and there. Most of them are just notes to make him more thematically unified though.

First and foremost, this is just a comment, but I'd say that Astromancy and Modern Magecraft Studies don't have much to do with the actual specialty of the character with seems to be dealing with plants. That's were the Faculty of Botany has their forte. A mage rarely is a student of a single Faculty, though. More often than not the people who are associated with a single branch are only staff. At any rate you don't need to change this, I'm just commenting because it seems like the intention of his magecraft and the way he accomplishes it aren't meant to work together.

Next:
[quote=@Crusader Lord]
In his own magecraft studies, however, Johann has innovated a certain line of techniques based on the ‘habits’ he gained while at the Clock Tower. Dubbed the “Joint Method”, it basically involves the creation and use of magcraft-treated joints utilizing different kinds of astrologically-aligned plants in order to produce different magical effects. The pinnacle of this innovative technique is something he has dubbed simply “The Weed Dragon”:  [color=ed1c24][b]By smoking a specially prepared joint containing a combination of prepared plants associated with each planet, he creates a temporary ‘inner universe’ in his lungs that allows him to recreate/use a dragon’s breath. [/b][/color]
[/quote]
I hope you mean this only in a figurative sense. Because breathing raw prana infused with elemental attributes is something way beyond the scope of even Grand Ritual level magecraft. Now, if it's just smoking really nasty stuff and using it as a medium for fire magecraft, it's fine (that's one of Touko's favorite tricks after all). The problem is that he doesn't have a fire affinity. He isn't unable to use fire-based magecraft because of that but he would be rather bad at it. Certainly not something that would be worth of a figurative title of dragon's breath.

Next.
You deal with 3 or so foundations in your CS. While that isn't impossible (many older families have a number of different Foundations burried in their crests simply because they picked them through time) it's hardly something worth it to dabble into so many unrelated fields and try to be an expert in them all. A mage certainly can be a master of the fundamentals (Such as Waver and Rin) but a true genius level expert rarely dips in more than one field (see Kayneth).

You might want to make your character more focused to earn that classification.

Your boon is ok, but just like the rest of the points above, it doesn't mix well with a character with a focus all over the place.

You don't need to change anything except for either his elements or the potency of his Eire magecraft (but if you do that you need to adjust the others correctly since plants would likely draw on Earth and would be weakened if the fire is strengthened). But know that, ultimately he'll be a very wasteful character so his powers might be limited during the RP to compensate for the breadth of his abilities.