Cook the briskets very early Friday morning to Friday mid afternoon. Something like 4am-4pm, so you can get ready and go to 8pm graduation.
Put the finished briskets in your oven on a keep warm setting of 150 degrees until the next day when ready to slice and serve. And it'll likely be some of the best you've ever served due to the long heated rest, you can easily hold briskets 18-24 hours this way and not lose quality.
I wrap in butcher paper towards the end of the cook when the bark is good and set with some tallow, then let it sit on my counter top for an hour after finishing, and finally I'll wrap everything up in clingwrap to make sure nothing leaks out in the oven and throw it in there on a cookie sheet.
If your oven doesn't have a keep warm setting, look up how to calibrate the temperature as most will allow you to adjust +/- 20 degrees so you can still get down to 150ish if the official lowest setting is only 170. Also remember that many ovens have an auto off feature so it's probably best to turn it off and then right back on every 6-8 hours to make sure it doesn't turn off completely on you.