Julie, when I made these bars in the molds, I sold them in small plastic bags, and encouraged customers to just apply them by rubbing them directly onto the skin. Later, I began buying deodorant-type dispensers, filling them with the liquid lotion, letting it harden, and selling them that way. They sold even better then.
You don't have to infuse dandelion into the oils, to make it insect-repellent. The essential oils are the most important ingredients for that. Dandelion is very good for your skin though, so that's a plus.
Because they're 1/3 beeswax, they won't melt, even in a hot car (I don't think). You could place the bar into a container with a lid, and then it wouldn't matter. But I think the bars might get a little soft, but not melt.
Both dandelion and calendula are good for the skin, and I think they are in the same family -- not sure. I don't have calendula growing wild here. But I do think calendula would be a wonderful addition, infused into the oil. People make just calendula salve for their skin.
Amanda, because they are 1/3 beeswax, they will not melt, but if you leave them in your car or out in the heat, they will get soft. I always keep mine either in the house or in my purse, and they stay nice and solid. I hope it works well for you!