What I would most likely do:
1. Filter, but carefully.
2. Most likely use the opportunity to use the walk signal, being careful to give pedestrians the right-of-way.
3. Probably carefully treat the stop sign as a yield sign, as they do in Idaho
Interesting enough, PennDOT's Bicycle Driver's manual gives some insight into Scenario #1:
GETTING THROUGH TRAFFIC JAMS
Traffic jams don’t have to stop you -- that’s one of the biggest advantages of bicycling in the city. But in the tight quarters of a tie-up, take extra care. Stopped cars in a traffic jam present the same hazards as parked cars: blindspots, doors and unpredictable starts and turns.
If there is an open passing lane, use it rather than thread between cars. If the street is completely plugged, pick your way forward slowly and with your hands on the brake levers. Remember, any car door could open!
If you’re in a traffic jam, you can be fairly sure that the cars will not move, since they have nowhere to go. But if there’s an open driveway or parking space into which a car could turn, you have to assume that it will. Look to see whether the car’s front wheels are turned. Move away from the side of the car as you pass, and try to get the driver’s attention as you approach the front of the car.
When cars are stopped, but not completely bumper to bumper, be very wary of cars from other lanes cutting across in the gaps. Stop and look before you move out into a gap. Be especially careful if the vehicle you’re passing, like many vans, doesn’t have a hood you can see over.
Don’t pass a long truck or bus in a traffic jam unless there’s a full, open lane next to it. If you ride close to the side of such a vehicle it may begin to merge toward you, leaving you no way to escape.
As you approach an intersection, change lanes to the same position as you would in normal traffic. Before you cross in front of a car to change lanes, make eye contact with the driver even if the car is stopped. When you reach an intersection, wait behind the first car at the traffic light. Don’t move up next to that car; drivers don’t always use their turn signals, so you don’t know for sure which way the car will turn when the light turns green.
These traffic-jam tactics are reasonably safe, but in some cities it may not be legal for a bicyclist to pass on the right or ride between lanes of traffic. On the other hand, it’s usually legal for you, or any driver, to cautiously disobey normal traffic rules when the road is “obstructed.”