If you are only doing the flat you could get up early that day and get it on and off before everyone gets there. Then you could do the burgers and whatnot for show in front of your guests. As for rubs keep it simple for your first then after a few briskets try experimenting. Fuel... I use lump, wood chunks or chips with some charcoal in my smoker (it is actually becoming less briqs as of late) but in my kettle I mainly use charcoal and wood chips...
Here is a good link for some tips!
Hope I helped... Best of luck!
Extreme BBQ Trailer, Backwoods Competitor, 2- 22.5" WSM, 22.5" & 18.5" Weber kettles, 2 Smokey Joe's, Blue & Red Thermapens, KCBS CBJ, Captain PJ's BBQ