Let me toss out a few of things to consider in your meeting. Using differential power to steer and to control altitude is a proven method. Model Aviation (March, 1997, page27) had a very nice design called RC Turbo Sport. A couple of us built them. They were capable of flying outdoors on a calm day, but any wind made them almost impossible to control, even by experienced RC pilots. Is there an experienced pilot in your group? The motors and radio equipment for the RC Turbo Sport are still being sold by a small company that sells them incorporated into ligtweight blimps and the like. The only name I have is S.G. Corporation, ElCajon, California 92020. Cost (1997)for a complete model, motors, and radio was $20USD. I have seen similar ads in more recent magazines. The cost seemed reasonable, but I didn't pay any more attention to them than that. BTW, Model Aviation is the publication of the Academy of Model Aeronautics (AMA), which is the major USA model avaition organization.
My personal view is that control by differential power is still a novelty and is very difficult to get the hang of. The weight of the extra motor and prop exceeds the weight of light-weight servos and other methods of control, such as, heated wires, to say nothing of the effects on drag and duration. From experience, I can tell you that controlling a polyhedral airplane with a single control (rudder only) is far easier than using differential power.
If you can express your design goals more concretely, I am sure many on this group will have much more to add. One thing you need to define is whether you want an airplane capable of flying outdoors and in what wind conditions? Will soaring (e.g., engine off flight) be allowed. What level of control do you need? Are there targets for weight, duration, load, or speed? Are there limits on wingspan and chord?
Good luck. John