Are there self consistent ways for people to believe that trickle-down economic policies should be encouraged but also to believe that small businesses are the primary drivers of growth?

Sure. Just to pick an obvious example, I might believe that trickle-down economic policies will benefit a subset of the population, and also believe that small businesses are primary growth drivers for the population as a whole, and believe that trickle-down economic policies should be encouraged because I consider benefits to the former subset more valuable than growth.