Hi, Just glanced at the project you've taken on. Good! Get all you can. Hope you have time to moisten the earth, that will permit you to cut plugs, with a sharp shovel, and lift out 6", 8", or even larger plugs~ they can be transported home in those plastic tubs sold for mixing concrete, and kept moist on the way. Lots of things will hitch hike.
all the plugs can be set together and watered, as plants come up and can be identified, you can move them where ever. So many of us remember plants we lost that were kept by those we love.
This is a great thing you're doing, you'll be thankful for the time and work it costs, and Grandmoma will be watching over your shoulder while you tend them.