Gary,
Besides what Tom D says, I would ask them to bring examples and discuss design philosophy of other bean field work they have done with limited topography. If they were smart, they would focus on that anyway in an interview, anyway.
If you like what they did on similar sites, you will probably like what they do for you on your site. As they talk, you will possibly get some of the general philosophy of handling that type of design, as well as perhaps some of the specific questions you had. You might also learn how they will interact with you.
Let the conversation goes where it goes, and you will probably learn more than in a real structured environment, even if every gca doesn't get the "same interview".
Opryland had a flat site, and I got the project, simply because I was the only gca to take them to play my flattest course (in Midland, TX) rather than my best couse.
As Tyler says, 40 foot of elevation change isn't anything to sneeze at! I have had sites (too many sites) with about 36 feet less elevation change.......
As Tom says, I don't think you have a conflict of interest, but I wouldn't get tied to one team. In your case, the good news is, the consulting engineer usually doesn't affect the team selection for golf course design. The bad news, from your perspective is......... the consulting engineer usually doesn't affect the team selection for golf course design.