Can I use a vanilla buttercream in conjunction with a whipped topping?

Hi! I made a coconut cake (with coconut cream) and for the topping, I made a homemade whipped topping (that will be topped with shredded coconut). The problem I'm having is that I don't have enough heavy whipping cream to make enough topping to spread between the layers, only the outside. So I was thinking of making a quick vanilla buttercream to use between the layers instead. Would that be too much, or would it be ok?