Hi guys....have rear axle, trans removed from my car. I have all winter now to putz on it. Goal is durable, painted underbody (for now, just the rear half of the car).
Car is southern car with minimal surface rust (more dirty than anything). Here are 4 preliminary ideas I have as of now. I'd rather not sandblast and deal with grit everywhere.

Do I:
wire brush it and wipe it clean - Rust Bullet, then topcoat body color?
wire brush, acid wash, rinse with water (not sure i feel like doing this under the car) - Por15, then topcoat body color?
wire brush, wipe clean - just epoxy primer, then topcoat body color?
Wire brush, wipe clean - Eastwood rust inhibitor, Eastwood rust encapsulator, then topcoat body color?

Garage is unheated, so chances are that I would have to wait until next spring to paint, if there's a product that can be applied in cold, great.
What would be some of your suggestions? Thanks!!