His main agenda, magic wise, is to spread his experimental discoveries. They are trivial, new parameters based on Glyph as a Range/Target/Duration. Cool ideas, but any magus is already able to invent spells with oddball parameters. This is more like an example of an optimal configuration. He is able to cast spontaneous Glyphs, but that is not really as useful as one may think. He has another Minor Breakthrough he is working on refining, using Glyphs as a Form & Effect bonus. Again, magi can already manage this using symbols (half bonus I think). The glyph system combined with the right script would allow for a wider symbol range though.
His deal is that he wants to work on spreading materials, his and others. He will trade you a grimoire of breakthrough spells for one of yours, and he will trade those he has gathered for those that you gather. For example, there is an Alchemy breakthrough in the Delivery to Barcelona thread hint hint, and Cornelius has gathered other trivial and minor breakthroughs he wants distributed.
As for pure correspondence, he likes to talk about the experimental process, and mentions that he thinks that lab work in the days of the early Oder was mostly experimental and was almost required.
He will gladly foster Vera for a season or so, and will ask if her sister can come visit. I will work out her sched to fit it in. He will take them on adventure.
Cornelius is a Bonisagus of Bonisaguse lineage, somewhat of a Trianomist in his social life, a Quaesitor Traditionalist with Transitionalist sympathies, an opportunist, a pragmatist, and a Seeker.