OK. Searing is out of the question as you need a piping hot pan. BTW, I would really, really, REALLY recommend getting a cast iron skillet as it is so multi-purpose. I use mine for everything from cornbread to roasting a chicken (which is far better than using a roaster as those basically steam as opposed to roast) to roasting veg to cooking on the stovetop. They are very inexpensive and keep for years and years. To me they are crucial if you want to do any kind of cooking. I could go on and on about it but won't bore you with the details.
So, you can do buttermilk. If you cannot buy it, it is easy to make. Just throw in 1 Tbsp of white vinegar or lemon juice into your measuring cup and pour in enough milk to get to 1 cup. It really helps to soak in buttermilk overnight but this is not absolutely necessary.
I have books on just rubs so I'll find a few great choices for you. And yes, you can use powdered ginger in a dry rub.