schnapps vs liqueur?
Generally, liqueurs are distilled alcohol with around 20% alcohol content and are sweet. I believe Schnapps is the German word for the same thing. There may be some technical differences for the serious drinker, but in a recipe they are the same thing.
If you want to drink it, buy Chambord, if you just want to bake, buy whatever comes in the plastic bottle.
My (limited) understanding is that a true European schapps is distilled from a fermented fruit/juice and, while very flavorful, is not really that sweet. Liqueurs on the other hand, are often sweet and syrupy. I think both would be fine on a cake but the liqueur might make the cake a little sweeter than you had intended.
I've made a few cakes brushed with Chambord (a liqueur) that were really yummy, and some Black Forest Cakes brushed (generously) with kirschwasser that were also yummy. But the Black Forest Cake was more aggressively boozy than the Chambord cake. I guess it depends on personal preference. Personally I think you can't go wrong combining booze and cake!