I was recently turned on to dry shampoo as a way to keep my hair from looking oily between shower shampoos. My hair tends to be oily and is dark brown. All of these dry shampoos are great, not only because they are talc free dry shampoos made in the USA, but also because they leave your hair smelling and looking great. There's no grayish hair look from these powders.
There are resources available to you if you need them, though. Also, don't discount cloth diapers if you have the means to launder them. They're often easier to get at free or reduced cost, not to mention they're way better for the environment, and you can be super smug about that. (Unrelated, but once you're done diapering your baby, those diapers really make the best dusting cloths and glass cleaners.)
I’m seconding the concern about starches as body powders. As a nurse, I know that starches do feed yeasts that can thrive on moist skin: along any sweaty crease like the groin, under breasts, under yer butt cheeks, etc. Hospitals once used talc, then starch-based powders, now mostly neither. I’m not being a nay-sayer. Just offering a word of caution. If ya get yeasty, maybe don’t put starch there. Can’t speak to powder combos with baking soda or whatever though.