I used my jam that didn’t come out as solid as I wanted. I switched to cherry jam and it was perfect as well. Just try out whatever you have or comes into your mind. What about a marzipan layer instead of the jam? Or both? Just play around. A ‘normal’ coconut whipped creme filling would be great as well but then the topping should be the same.
To combine well the wet ingredients I usually use my mixer. It’s fast and efficient, just have to pour the liquid into the dry ingredients and stir again.
If the cake is for a special day you can decorate on the chocolate for the occasion. Do it when still wet.