Yes. Sprint is ALWAYS available, AA is on the same button as on Reach (Right bumper, for me).
I saw no new weapons in multi. Frank showed off a short campaign demo (10 minutes of an early level in the game), and there was some sort of energy-based covenant rifle that looks pretty cool. (Didn't get to see it in very much action; it came pretty late in the demo, and depending on who was running through, there often wasn't much left alive by the time it showed up.)
I didn't experiment with any of the loadouts that used anything but Promethean Vision - sorry. (Both of the first two loadouts had that as the AA)
There were almost no weapons on the map at all in the games we played. (I'd say there were none, but I seem to remember a needler or two lying around - I guess maybe a deady guy could have dropped it, not sure.)
Ordinance drops are pretty cool. When you earn one (I don't know what I did to earn them), you get a little thingy in your UI that pops up - three choices, mapped to three buttons on your D-Pad. Pick your drop, and it'll appear in the default location for that power weapon soon after. That is: Let's say we're talking about Powerhouse. When the game starts, there are no Rockets in the outlet under the station... but as soon as someone earns a drop, and picks Rockets, they'll pop in there. Everyone gets notified that they're about to drop - but the dropper obviously knows a little sooner. So you can either get there first, and snag 'em... or get there and set up a trap.
WHAT THE HELL AM I DOING STILL TYPING? I'M SUPPOSED TO BE PACKING!