Our basement is full of miscellaneous paints left by the previous owner, who had the house painted before she sold it. Among them is Zinsser stain-block primer. Is this a primer that would also be appropriate for added mildew resistance, or do I need to buy a mildew-specific product? (We'd love to use up paints we already have if possible!)

On the paint note, the bathroom is currently painted in BM standard interior paint (can't remember what it's called, but their basic latex wall paint in a flat finish). Our kitchen and bathroom are the same color, and we have extra paint for the kitchen that matches, but it's BM Satin Impervo oil-based in an eggshell finish, which has been great for wiping down splashes in the kitchen. Would this paint likely be more moisture/mildew resistant than the standard wall paint? (We're considering painting the area around the shower in the Satin Impervo and then just leaving the other two walls alone, since they don't have moisture issues and the paint's in good shape---so then the color would match, but the finish would be slightly different. And we wouldn't need to buy any new paint...plus, we're about the redo the kitchen and paint it another color, so we won't need the extra for anything else anyway). Will this look bizarre?

Ideas? Or should we be looking for the mildew-specific paints that are out there? (Oh, and yes, the bathroom is vented with a newish fan that has ample CFMs for the room size, but it is apparently not sufficient to keep the moisture at bay with two back-to-back showers!)