Advice for a Coliseum newbie.

For the exhibition, you're probably OK with day-of-game seating, although even Coliseum vets probably aren't sure how scarce the upper deck closure will make walk up tickets yet.  

For hotels, you're right, it's not a nice area.  There is a Courtyard (probably listed as the Airport one) that's nearby, and they were nice enough to give me a ride to the game in their shuttle; I took a cab back.  You have immediate access to the BART there, so another option is to take it to the 12th St/Downtown Oakland station and stay there.  There are a few Marriott owned hotels there, and a Best Western about a nine-block walk at the corner of Broadway and 3rd, which might have pretty reasonable prices.  There will be more to do around there.

1. The bleachers are always fun for real games, but I don't know how rockin' they'd be for an exhibition (maybe ask saint). I'd probably go for the best available, which would be lower level, either behind the plate or down one of the lines a little bit, depending on your preferences.
2. I don't imagine an exhibition would sell out, even against the Giants. In fact, since the game is included in season ticket packages, you can probably find someone unloading decent tickets cheap, either at the game or ahead of time on craigslist.
3. Can't really help you.
4. Sure. As booya says, it's a beautiful park and easy to get to. Take BART to Montgomery St., then walk 15-20 minutes down 2nd St. to the stadium. Be sure to stop in at the 21st Amendment for a beer on the way. You may want to get a ticket in advance for this one, though, as <Telephone Company> Park tends to sell out, and it will probably cost you a bit more.

As for #3, BART runs a shuttle to/from OAK airport that costs $2 one way. If you're going to the game directly from the airport, or if your hotel is right on a runway, you might think about just taking the "AirBART" shuttle from OAK to the Coliseum BART station and then walk across to the stadium.

#4: If you're gonna be in the area, yeah, try to get to the SF park. It really is awesome. And if you do plan on going, let me know and I can buy you a drink -- I work 2 blocks from the ballpark.

On #3, there plenty of uppermid range hotels hotels along Hegenberger Road, which makes a 2 mile straight line from Airport to Coliseum.  All of them are OK; all provide lots of American Airport culture and zero Oakland culture (except the circular purple hotel, which is another story entirely).  There are some very low-end hotels along Coliseum Way North of the 'seum (where Wolff's Plan A park would have been) that offer perhaps more than you want to learn about "Oakland culture," in the most reztipsy of senses.  If an important goal is to stay in a place that feels like Oakland in a good way, try the Jack London Square area--range from Waterfront Plaza to Jack London Inn, all nice, none cheap.  Ribs at Everett and Jones BBQ, Jazz at Yoshi's, a decent night's slice of Oakland.  A bit further afield is a Motel Six, maybe 1-1.5 miles from Jack London Sq, along Embarcadero, perhaps a bit less pricey.

All of these (except the sketchy Coliseum Way ones) are a walk or bus or cab away from BART.  And you won't want to walk from BART to Jack London at night, but there's a cab stand at 12th Street BART station and it's a short ride.  BART will get you lots of places but you need to tack on soemthing to get to a lot of Bay Area spots.  This will also prove true if you head to SF, which is of course a great city worth seeing, ballpark or otherwise <ducks chair>.

If you need to save money on your hotel, folks seem to be able to get the Oakland Airport Hilton on Priceline for $55-60 per night.  Hotels in this area (Oakland/Berkeley/Emeryville) are expensive, so this is a good value.  You could also get lucky and end up at the Marriott in Downtown Oakland, but you're most likely to get the Hilton if you use Priceline.  IMPORTANT: Do not bid for anything below 3 stars or you could end up someplace nasty.  I have strategies for getting your best price on Priceline.  E-mail me if you want advice.

Experiencing Oakland (my top 10 in no particular order):

1. Eat at Le Cheval on 10th and Clay for a busy/crazy large Vietnamese meal where EVERYONE from the Mayor to EMTs eat.
2. Have a fantastic $2 Vietnamese sandwich at Cam Huong on Webster at 9th.
3. Enjoy great Cambodian food at Phnom Penh House on 8th at Alice.
4. Eat crisp yuppie pizza or swanky organic Mexican food in the Temescal district (51st and Telegraph) with dinner at either Pizzialo or Dona Tomas.
5. Have kick ass Korean stews (esp. #3 on the specials menu) at Sahn Maru (Telegraph at 43rd) or Korean BBQ at Oghane (3900 block of Broadway).
6. The best Ethiopian food in the area is at Cafe Colucci on Telegraph at Alcatraz.
7. A fried chicken sandwich to die for (you will never be able to eat chick-fil-a again) can be had at Bakesale Betty (Telegraph at 51st).  The scones are amazing as well.
8. Hoist a few tasty Belgian beers (or Hendricks & Tonics) at Luka's Taproom on Broadway at West Grand (23rd).  Great food and DJ action as well.
9. Visit Heinold's First and Last Chance (http://www.heinoldsfirstandlastchance.com/)--the only authentic thing at Jack London Square.  Closes absurdly early (midnight?), but it's worth a visit to have a beer by gaslight and try to negotiate the floor that's been askew since '06.
10. Experience yup-scale Rockridge with a meal at Pearl Oyster Bar, Grasshopper (Asian small plates & GREAT cocktails), or A Cote (French small plates & GREAT cocktails).  Trendy, not cheap...but yummy.

If you get a Plaza Level ticket, be aware that Row #1 is the walkway (yes, this seems NOW like a no-brainer, but I didn't know that the first time I went to the Coliseum, and I had people milling around, blocking my view and crashing into my knees during the entire game). If your seat is lower than about Row 6 in the Plaza Level, your view might be at least partially blocked by pedestrians and the safety rail.

#4:  I also think it's worth a trip to Phone Co. Park... and as booya pointed out in the first comment, it's fairly easy to do via BART + walking or streetcar.

I'll have a spare ticket for the Wednesday game (4/5) if you're still in town then and would like to use it...  :)

1. The coliseum is like most parks, except more so ... the less you pay, the further away from the action you are. Only the coliseum was built out instead of up more than is typical today, so the cheaper seats are further away. That said, I love the view from a Sec 220-222 ... not too far away, but enough distance and height to really be able to see what's going on. The bleachers are fun, but the view is distant and you can't see what's going on in the OF under you.
2. I find it hard to believe the exhibition will sell out ... and even if it does, there will be scalpers selling for face value or, likely, below ... but you won't have as much choice in seating ... though there's a decent chance you'll get better tix than are available today.
3. The hotels in the airport area are all in perfectly safe but horrendously boring neighborhoods. There is nothing at all to do out there ... unless you're a golfer, there's a brand new course in that area. You could also consider staying in a different part of town, Jack London, perhaps where there's a lot more to do and better food to eat. The Coliseum and the airport are an easy BART ride (and airport shuttle) from most of Oakland.
4. I'd absolutely recommend you check out PacBell ... it's a beautiful park and definitely worth seeing. The ferry is nice ... though it will likely be a bit cold heading back, so you might consider BART for the return ride. I'd try to pick up a ticket in Row 1 of the Arcade if you can ...