I'll bite,
first year we attempted it we were a team of four, a few were not the strongest riders, I got the bike in Ojos which is just out of town and rode it to the coast, we switched riders and I was supposed to get the bike back just before heading into Europan and finish, the bike never made it and I had to ride backwards on course through the night to find our rider...it sucked. The section he was supposed to ride I could drive a minivan through, so my first word of advise is make sure your whole team is on the same page with similar goals. Know your bike, agree upon what types of items you will carry in your camelback and make sure everyone is strong mentally.
The second year I went back for redemption and took all of that out of the equation and rode the whole thing solo. I am not in great shape, I am not a great rider, I'm pretty old now but I am one stubborn SOB and I finished. I got passed by 2 Trophy Trucks and that is a little life changing but manageable.
As far as lights go if things go well you don't need them, if things don't go well you do, so better to have them. I rode without changing an air filter but had one in my bag. I rode a D606 in the rear and rode for another couple months after the race on the same tire. They wear like Iron, never really hook up well but tough to flat. Up front I was on a Bridgestone M403...kind of the same deal. Both those tires suck in the sand but I was on an XR650 and just grabbed a wristfull and let the tractor do its thing. I am a singletracker not really a Baja guy but I got talked into this Baja thing. I am better when it gets nasty and I'm a wimp when its fast. Baja is all fast, the stuff they call technical is like 4th gear instead of 5th. I lost like 5 teeth on my rear sprocket and gained 2 on the front compared to my usual. The course was really easy both years other than dealing with Trophy truck sized whoops....they look more like small double jumps. The first year we dealt with the whoops after Ojos and rode the coast to Europan in the Afternoon, that was better for me. The second year when I rode alone they ran it reversed so I had to deal with the big whoops in the afternoon after riding 300 plus miles and it got tiring. You could skip them like normal for a few, then start to try to rythm style hook them together into little doubles and eventually get tired and just saw through them like a row boat on the open seas. Wasn't too bad but I definitely went through them better fresh than later in the day.
We are running the 1000 this year as a 2 person team on a 650, I guess technically a 3 person team but the 3rd is really the sponsor, he runs a few miles after the start and if all goes well we will finish the rest. Good luck!!!
Don't let the whole race thing get to you too much, enjoy Mexico and the time you get to spend there riding. I let it get to me the first year and left sort of angry we didn't finish. That drove me for the next year and in looking back now I really had a lot of fun. I wish I would have enjoyed all the moments instead of just focusing on the task at hand that for me was finishing the race. I guess its just the blue collar work ethic that I got hit with by my Dad, it's what drives me and I'm too old to change...but if I could change myself that's what I would do. Enjoy the moment, enjoy the time, make it feel less like work and more like what it is...a bucket list item!!!!