Yes, you can absolutely make cake ahead of time. It’ll keep at room temperature for a couple days or you can refrigerate it as well. When cake is refrigerated it’ll set up firmer and won’t be as crumbly as well.

I haven’t made it with Bisquick, I have always thought Bisquick was more dense and made very heavy pancakes, so the end result would most likely be a much heavier cake. You could give it a try, if you do, let me know how it tasted. I like light fluffy pancakes and use Krustez brand pancake mix and it gives great light fluffy pancakes, even when make pancakes I add more water so the batter is thinner and the pancakes taste lighter. Do you love pancakes with Bisquick? I like it for biscuits, but again they seem on the heavy side. If it’s all you have, by all means, give it a try. Whisk it in a bowl before adding other items, or sift it to lighten it up would be my best suggestion.