Was able to talk to my accountant, so I think I have my answer with reasonably good news.

First, a couple responses to notes above:
- Yes, my company management is aware of the trip
- Yes, there will be significant business content and networking on the trip.

Now, for the tax deduction:
- Since I'll be getting a 1099 from the trip provider, I'm essentially being treated as an independent contractor.
- The way my account described the situation, for the purposes of taxes, I'm essentially being paid a lump sum by the provider, and will then be able to deduct the relevant business expenses on the 1040-Schedule C, which will amount to the entire amount of my portion of the trip.
- He amounted it to a similar scenario where (for example) a lecturer is invited to speak at a conference for a flat fee of $5,000, including all expenses. The lecturer could deduct all reasonable travel expenses, and pay taxes on the "speaking fee" portion
- I will not be able to deduct anything for my guest's travel