I intend to run Waterdeep: Dragon Heist in the near future, and I'd like to keep meticulous track of the date on the Faurúnian calendar as the adventure progresses. This is to make proper use of Waterdeep holidays and other things as my players begin the adventure and make their way through chapter two, as well as to put them on a clock once the fireball gets the story rolling. Does anyone have any good tips for:

• Starting Date of the adventure. I'll be running this with the Cassalanters, and I'd like them to be able to spend time at their tavern in Trollskull Alley for at least a little over a month. I was thinking maybe Mirtul 28, but I'm open to suggestions if this much space is a bad idea.
• Date of the Fireball explosion, with the starting date and the Founders Day festival kept in mind as the last day of the adventure.
• Running the holidays in fun and exciting ways. Currently, Trolltide, Guildhall Day, Dragondown, and Founders Day are the holidays that I'm currently aware will fall into the campaign's timespan. I'd like to make these cool events, so tips and/or resources for running them would be great.
• Tracking the calendar as dates pass. Having an easy way to to this will be pretty important for me, so that I can lay out and easily edit a general timeline for the adventure on the DM end of things.