Is it strange to set everything except the plates and bring them out at the last minute if I'm serving family style?
Yes it would be strange. Not only would it be strange, but it would no longer be "family style," nor would it serve much of a practical purpose. Warming the serving pieces in the kitchen, plus the sheer amount of food served in them, should be enough to keep the food hot -- at least for the first go around. Warm plates are useful for getting food from the kitchen to the table, and until enough of the table is served that eating begins. But they don't do much to keep it hot once its on the table. On top of that, the "good china" loses heat more quickly than the everyday heavy porcelain because it's so thin.
Family style means the table is served, not the individual diner. Not only would it mean extra trips for the people making and serving dinner, but if the plates were brought to the table hot, they would lose most of their heat while waiting for the food to be brought to the table and then attacked passed. So, on top of everything else... pointless.
In my experience carving at the table is almost always worse than carving in the kitchen (or wherever) and plattering the meat before bringing it to the table. Most festive tables don't enough room for a carving board, carving directly on a platter instead of a board screws up knives and platters, and it takes so long to pass the plates and load them with meat that the flow of dinner is broken up.
It's not easy to make it look good, either. A hundred years ago, upper and upper-middle class men used to take classes on how to carve gracefully; but unless you really know what you're doing it's not an easy task in front of a room full of hungry diners -- especially with something as difficult as a bone-in leg of lamb. On top of that, very few homes have sharp knives or the right kind of carving board (big enough, with a channel to catch the juices). I worked my share of carving stations when catering, but could never make carving at table work at any of my own parties.
Back in the day, chargers insured the diner never saw an empty place nor an empty plate. The old etiquette was that when the charger was removed, it was immediately replaced with a full plate. The new etiquette is slightly different. Frequently, all or part of a clean dinner service is placed on top of the charger, giving the diner the opportunity to appreciate the beauty of the clean china. But service itself is not much different. The entire, clean setting, along with the charger is removed from the table as the first course is served.
New etiquette or old, chargers are not "family style." Because chargers need to be removed from the table so soon before the food is served, they require waiters of some sort. And unless we mean radically different things by "family style," even if your sister acts as waitress, people running around doing stuff like pulling chargers and replacing them with warm plates after the party is seated isn't in it. And if the chargers are replaced before the diners sit than the plates will be cold by the time the food is brought to table.
Etiquette shmetiquette. This ain't charm school, I ain't Miss Manners, and you're free to make your own rules for your own friends and family in whatever ways please you. If you want chargers, use chargers, says I.
The first part of successful entertaining for an over achiever is not getting food to the table hot, but learning to cut yourself some slack. Everything will not be perfect. Some things cannot be perfect no matter what you do. Hold on to some perspective and remember that even at Downton Abbey, with a full compliment of footman carrying the "family style" platters to each guest, food got cold. It's your party, enjoy it.
Edited by boar_d_laze - 4/6/13 at 9:29am