What motivates us?
That's an interesting question, but not one that necessarily has only one answer. When I first viewed your poll choices I probably would have picked
"Flying &/or maintaining high performance/kicka$$ planes" except that whenever I try to call a Stearman a high performance airplane I start to giggle.

But I love to fly her on warm, sunny, CALM evenings, and I love opening the cowlings and peering into her innards with a flashlight and an inspection mirror, or jacking her up to pull the wheels and adjust the brakes - so much so that I'm restoring another one to keep her company.
That said, it's very, very important to me to know the
detailed histories of all of my airplanes, not just in a general sense but the actual specific details of the lives that these individual airplanes have lived. I know for example the name of the young RAF cadet that pranaged my BT-13 in Florida - I have a treasured copy of his class's graduation picture that was taken just a few days after the accident. His name was Chamberlain and he wasn't washed out but went on to fly Mosquitos and was killed in '44 on a night intruder sortie in Europe. It's important for me to know that, although I secretly suspect that most times I'm the only person in the world to whom that matters anymore.
The history of the battles? Somewhat, although I'm the first to admit that I'm more of an aircraft technical historian than a military one. I can tell you far and away more about how a B-24D differs from a B-24J than I can about why the Ploesti attack was not the wisest tactical use of four engine heavy bombers.
The sacrifices of the pilots and people? Yes - it's very important to remember those people and the sacrifices that they made because as long as we do that, as long as we remember what those people had to do and had to give up, had to live through and why, then maybe we'll never let it happen again. So if flying my Stearman around where people can see and hear her, and taking her to airshows and fly-ins and pancake breakfasts where they can walk up to and touch her and look and sit in the cockpits and ask questions - if that makes people stop for a moment and remember the past, you won't hear me bitch about the price of fuel.
Living history/reenactment? No. I'm sure this isn't fair, and I'm sure it's an opinion based on ignorance, but reenacters generally strike me as "wannabees". (Especially when they won't/don't take their sunglasses off indoors.)
Pretending I'm a famous military aviator (Walter Mitty)? Nope. Although while looking at a pile of metal shavings at the bottom of a paper paint filter and noting all the bearing material in it, I have been guilty of wishing I was a certain rich warbird collector so I could just whip out my cell and call JRS and order a new one!
But I'll add one to your list;
the love of tangible history. My girlfriend was in the hangar a couple of weeks ago looking at my very derelict Vultee and questioning my sanity (or lack thereof). She even used the dreaded "j" word - the one that rymes with "skunk". But after she'd had her fun and made her little pokes at me I started showing her around it. The gearbox still full of grease that was probably last greased while Jimmy Doolittle was still walking through China thinking he was gonna get court martialed when he got home. The nuts and bolts holding the throttle quadrants to the frame that hadn't had a wrench put on them since before Pearl Harbour. The electrical schematic inside the junction box that had just seen daylight the day before for probably the first time since Dick Winters first strapped on a 'chute and a jump knife. The original paint sprayed by Rosie herself. All of these little details suddenly brought the past to life for her. The fourties, the War, Hitler... all of that had been real because here was the proof right in front of her that she could reach out and touch and feel. It wasn't just a couple of chapters in a history book anymore, it was
real after all, because here was the proof.
(Whether or not it'll ever fly again is still something else for her though!)
Now if you'll excuse me I'm off to battle the evil "Yellow Baron" in his J-3 Cub. I'll be the guy in the orange Champ. The loser is the guy who comes home with the least ammount of toilet paper in his tail brace wires, and the loser has to buy the first round!
Dan