A Buff Brahma over a Rhode Island Red will get you a mixed, reddish chick. You would get a mix/mutt/cross. But yes, if everything is good with the parents, health wise, of course, you'd get fertile eggs and live chicks if you incubated them.
Chickens cross breed. They don't know they are different breeds and could care less.
Worth giving it a try . Brahma female has not laid eggs for last 5 months,even it had laid earlier strange enough so was thinking of introducing a Rhode Island Red female .