Check about the wool allergies, but honestly it may not matter. I am allergic to wool so never wear wool sweaters, but encased in a quilt sandwich a wool batt does not bother me. For a lot of people, it is the quality of the wool and how it has been manufactured that bothers them. Wool fibers have little "hooks", and that's what gets me. I think many wool "allergies" are really simply sensitive skin that reacts to the hooks.
You cannot beat wool batting for warmth, comfort and wear qualities. The wool batting made by Hobbs and by Quilter's Dream are needlepunched for stability; those are the only two brands of wool batting I would consider using. Just want to make sure you don't rule out wool for people who don't like to wear wool sweaters!
Also, I second the recommendation to use flannel as the backing. Really helps so that the lap quilt stays in place. Also second the recommendation to permanently label the quilt in some way (embroidery probably the best) so the quilt doesn't go home with someone else.