It’s not uncommon to use Vienna malt in light beers, it’s another tool in the chest. HSA does add color to beers, I’m not sure about CSA.
If you use SMB in the mash, it’s used as a bleaching agent in the food industry. SMB will keep the color quite light. It has been used in the mash in the past in the United States. I believe Miller used it in the 60’s due to darker malt from their suppliers. They wanted the lighter color because it’s what their customers expected.