Hopefully Hants or someone will chime in but I think you would be fine just registering in your name and with the 40. If something changes, that's just the way it is
- The only deal with the vehicle is that your "card" you'll get would show that you have/are driving a FJ40 vs. whatever you show up in...Not a big deal.
If you can't show due to work but your dad can I don't see why he can't take your spot (just notify Hants) and if the stuff really hits the you know what there are usually a lot of people wait listed that will want your spot. Just try to give the committee as much notice as possible to fill your spot.