I've had halimeda in my DT for years and of course it's on a light cycle. Never had probs with it. I've never had shaving brush, so don't know first-hand. But I haven't read issues with shaving brush being on a light cycle. Both are excellent macro algae though. They need good calcium levels and are intolerant to excessive nitrates and phosphates, so if they are doing well in your tank, it sounds like your water parameters are doing good.
125 gal. reef w sump/refugium & 8-bulb 640w T5's
45 gal fresh w/plants + CPF lighting