Rinshin, I think the apricot Bavarian cream recipe can be halved with no problem. The biggest issue to me would be choosing the right pan sizes for the cake layers and the assembly. May be 6" for the cake layers and a 7" spring form for the assembly would work. But if the cake did not work out, you could always serve the Bavarian cream by itself. There was a little left over from the cake assembly, and I had it for breakfast the other day. It was lovely by itself.
I'm thinking that this recipe is quite versatile, I can substitute peaches, mangoes or even strawberries for the apricots.
Good luck with your cake.