I am wondering if these Betty Crocker cake mix flavors are very different or if they can be used interchangeably. I am making banana, lemon, and white WASC and usually use just the white as my base mix. However, a good sale got me to buy the vanilla and the french vanilla. The french vanilla I used for a caramel cake, but I still have some left. Is there a vast difference in the flavor profile? Thanks!

There is a difference, but not a big one. I think it might be most noticeable in lemon cake, rather then the other flavors you mention

I use the white / french vanilla / golden vanilla interchangably, depending on what's on sale at the time. I always use whole eggs instead of egg white for the white cake, so my cakes naturally have a slight yellowish tinge. I do promote all three as my "white" cake.

I use the WASC recipe with all three also.