Algae is normal during a cycle and during the few months following it. It will most likely get much worse before it gets better, but with the right steps taken it will get better. You have to find the source of the algae, too long of a light period each day/bad lights, too many nutrients (phosphate and nitrate), not enough flow or most likely a combination of these are the most common causes in my experience. Do you plan on a clean up crew? If your ammonia has dropped and is holding at 0 for a few days in a row it's time to consider adding one

They will make short work of the algae.
Nitrite is believed to be harmless in marine tanks. There's an article out there detailing the experiments with results. I don't have a link though sorry.
Also, please don't use fish to cycle the tank.
You know when you go into a freshly cleaned bathroom and the bleach/ammonia smell is really strong and sometimes it hurts to breathe? That's what a cycling tank is like for fish 24/7.
I would just grab some table shrimp and use them. They're already dead so there's no suffering involved, it's cheaper and it's 1,000,000,000x easier to take out of the tank than even the slowest damsels.
Good luck!