Matt, somehow the simplicity and precision of SV cooking with your Anova rig while camping with limited packing space seems incongruous. Too many things can go wrong at a camp site, leave Anova et al at home if you can.
I'd SV cook the steaks to the desired degrees of doneness at home with or without seasoning. If i were cooking for 8 i'd leave them unseasoned to start. Carefully label each steak by doneness and chill or freeze depending on how far into the future you plan to serve them. Frozen travels best and helps keep beer cold.
If you're going to grill the steaks over an open fire pit let the fire get down to a wide bed of glowing coals. Bring extra long tongs and a grate to make things easy. If you lean towards the more rustic side of camping impale the gently warmed and dried steaks cap-side towards the hand on peeled and soaked forked sticks, amply season or not, and let each hungry guest sear her own.
Should anyone drop a steak onto the coals that's alright, it's just a little extra browning. That's why you brought the long tongs and paper towels for wiping off ashes.
Make it a great experience.