Well, I was going to recommend a gondola or a tram, but it looks you are committed to this weekend and tackling the fear head on. There are many different approaches to dealing with fear. Which ones will work and which ones won't is a crap shoot. The only way to know for sure is to ride the lift. You need to get buy in from her that she is willing to try and knows it could happen again.
For the fiance's case, it sounds like the moment of truth is getting off the chair. If you can find a plastic chair, bring it on to the bottom of the bunny slope and practice getting up and skiing STRAIGHT off. If you can't use a chair, practice a 90 degree hop turn and ski off instead. If possible do it on a pitch that is as steep or steeper than the lift exit ramp, and has a flat runout where one comes to stop without turning or wedging (or at least minimizes the need). When practicising, emphasize that the knees and the hips have to come forward immediately after standing up. The idea here is to ingrain the movements necessary for a successful lift exit and keep the requirements to a minimum. An add on to this is to add sound keys like "ready, up, forward" to practice the timing involved.
Being an evil instructor, I sometimes use a method I call Power Assist. When getting off the chair, I go "ready" and grab the student either by the arm or all the way around their waist and "up" is when I pull them up off the chair and drag them screaming down the ramp. Make sure you are on the inside position before you do this. As long as they don't fall, they usually won't sue you.
Speaking of instructors, have you thought about hiring a professional to do the job as a means of insurance for your marital status. Friends don't let friends teach fiances.