Desirai,
Cannas that do not produce seed often produce pollen that has some degree of fertility. Your success may depend to repeated attempts.
There is no way to accurately predict the results of a successful cross pollination. Hybrid cannas carry a number of dominate and recessive gene possibilities even when backcrossed with their parent. With two distinct cultivars the seedlings receive half of their chromosomes from each parent. The results typically produce a few radically different plants but most will have strong physiological characteristics of one of the parents.
One would likely have to make a hundred plus crosses of the same two parents to determine a "typical" result. That�s what makes hybridizing interesting.
Kent