Yes- This is ok for all available rewards except limited rewards (otherwise the limitation fails) and complete bicycles (high shipping cost). Just add the amount for additional rewards to your pledge (without additional shipping cost). After project termination you will receive a survey where you can specify your desired combination.
The different options all have the same price and when you choose a reward you don't need to specify these optinos exactly (because Kickstarter offers no way to selec options). After project end we will send out a survey where you can select the desired options.