Your stock sounds extremely similar to poplar, and I suspect being hardwood, will not take stain well, (just like poplar). I would recommend a low-VOC (for "tree-hugging
Van) paint instead. Or, if you like the color and grain, a polyurethane finish (high-gloss on the inside, for sanitary purposes).
Can't help you with moisture expansion/contraction issues, as we don't have that problem here. In fact, I cross-grain glue everything!