Nola, it will definitely be colder and wetter than what you experienced last year, but I'm sure that you're expecting this. You will also have some good weather days as you progress. Make sure you have the type of wet gear and footwear that you are comfortable with. Personally I use an
Altus poncho as it covers my pack and in the early spring and late fall I now add a super light pair of Gortex rain pants to my gear (for ages I walked in shorts with short gaiters and this works too). My boots are always Gortex lined, but everyone has their own recipe for footwear and rain gear!
Perhaps use different colour dry bags in your pack. I like using these because not only does it keep my gear dry, but it helps me to quickly find things. Clothing layers are the key as others will tell you. As for the number of pilgrims, this changes each year, but this site will provide you with the statistics so that you can get a sense of numbers.
https://oficinadelperegrino.com/en/statistics/
I believe that you will find most albergues open, but you can easily sort this out with the resources available on this forum (refer to Resources section) and the Confraternity Guides are good sources as well as many other online resources.
There is lots of experience and information on this form. A few searches above will bring up more information than you probably want to know!
Have fun planning your walk, but don't worry, you'll meet lots of people, see lots of storks and the spring flowers will eventually come out to cheer you along each day!!