Will the Keukenhof gardens be in bloom by March 30th-April 2nd?

Keukenhof thinks so. It opens 22 March 2018 and will be closed 13 May 2018.
https://keukenhof.nl/en/#plan-your-visit
The fields around Keukenhof will be at various stages of blossom but part of the process to fatten the bulbs is to lop the flowers off.
What flower market do you mean? The wholesale market outside the airport is a vast industrial sales exchange, intriguing but not esthetic.

The gardens will open March 22. Just like in most gardens, flower opening depends on the weather, and nobody can predict how early spring will warm up. But you can get up to date information on blooming on their website (once they open). So maybe play it by ear and check once you're there. It is truly a fantastic garden to see. We spent the whole day there. As to whether it will be warm enough for a bike ride? My crystal ball is in for repairs. Lol. But historical daytime highs range in the mid to high 40s F.

I think you be talking about the Floating Flower Market
https://www.holland.com/global/tourism/destinations/amsterdam/floating-flower-market.htm

Keukenhof is hit or miss that time of year but the inside flower galleries there are interesting though

We have been to Keukenhof 3 times over the last few years (mid April to mid May). Each time we spent practically the entire day. Never as early as your proposed dates, but it was spectacular each time. Our most recent visit was May 2017 just days before closing. I worried the flowers would be spent, but was happily very wrong. I honestly am beginning to believe that cadres of gardeners sweep through the gardens all night, cleaning and replanting for the next day. Reminds me of a botanical Disneyworld where just about everything is managed and maintained wonderfully. The flower market along the canal is nice but would not be a substitute for Keukenhof in my book. I love flowers and gardens, but walking the block or so canal market, looking at stalls selling flowering potted plants and sacks of bulbs took no more than 20 minutes. I hope it works out for you, and safe travels.

Do you mean the Aalsmeer flower auction ? Better be an early riser for that one . As mentioned here already ; interesting to see the Dutch auction bidding process which starts High and keeps going Lower . Buyers sitting in a special area with a button to press when they see a lot to buy. These lots keep riding to the auction floor .After being bought they then ride out the door to ? Trucked to ? or going to the nearby airport on their way to the US ? I found it indeed interesting but you do not really get to enjoy flowers .

We are planning to visit Keukenhof on March 22 or March 23 (depending on which day has the better weather), and are crossing our fingers for a good showing. I've been checking out this website for info (https://tulipsinholland.com/2017/11/when-are-the-tulips-in-bloom-in-2018/), and in mid-March, they will begin their tulip watch blog/weekly updates, so that may give you a sense of how it may be going. Also, I've occasionally been checking the weather to get a sense of how warm the winter has been there (it's been relatively warm, I think).

Keukenhof is not a natural bulb field. It is my belief (no research done ... ) that many of the bulbs on view were started indoors, and a put out in waves, so that there are blooms all "Kukenhof Season" long. I am not slamming them, but simply describing common public garden practices.

No one can possibly answer questions about climate and season in one year as opposed to another year.

Since almost all of the flowers at the Auction are about to be sold, they are naturally in prime condition. It is an entirely indoor experience, but very worth the outing. It's not so convenient to do both by public transportation on the same day, I think. (We had a car - but I'm not advising you to rent a car just for flowers.)