You have many options. You could park right at the airport and not have to deal with shuttles at all. Here is a link to the Mitchell parking info. You will note that it also gives an approximation of how full the lots are. Of course at $12 per day it is more expensive. http://www.mitchellairport.com/parking/
Another option I've used when I have a large group with lots of luggage is to drop off some of the luggage and some of the people at the airport, then park the car and not have to deal with all the luggage on a shuttle. Those who stay with the luggage can just wait for the car parkers to return before checking in. With many airlines you can also check your luggage at the curb, which may be convenient if you have a lot.
I will say this about fastparkandrelax. They can give you two parking spots next to each other since you seem to be concerned about getting separated.
If you need ideas about a meeting spot, I'm not clear what you are asking, do you want the name of a restaurant or something that would be convenient? Sorry, I'm just not clear what you are looking for in a meeting spot.
Since this seems to be causing some anxiety I suggest you leave home extra early. Nothing makes me more anxious than when I am in a rush. Also, not sure when you are traveling, but as long as it's before the Thanksgiving Holiday I don't think the airport parking lots will be that full.