Heat cooking oil in the pan until it starts smoking. Hey presto it’s seasoned. Tomato will not strip it, nor will soap. Intense scrubbing will.
Cast iron is so easy to care for. Just don’t stick it in the dishwasher or let it stay wet after washing.
Put nails in at an angle, and alternate the angle so a row of nails looks like a row of Vs. Whenever reasonable I’d still go for screws though.