So, here are a few reactions to your questions.
1. Typical weather. Sadly there seems to be very little of that. Be prepared for early spring temps to hot. I have walked the Norte in May-June and June-July and had a little bit of everything
2. Recommended clothing -- layers are always a good idea. But everyone's temperature comfort zone is different. I am one of those who always wears a sweater in air conditioning, so I tend to the cold and have always used a sleeping bag and a fleece. Others who are always sweating find a liner and lightweight clothing to be perfectly adequate
3. Albergue and lodging availability -- you are in full Camino season, all will be open.
4. Blankets -- I don't remember and try not to use them because of bed bugs.
5. Bar/restaurants -- again, everything is open.
6. Words of wisdom -- my own particular soap box is that it is oh so worth it to get off the camino and follow the many coastal paths that are nearby. The camino is always near the coast, but frequently it takes you on the side of a highway about a km away. One of the pinned posts in the subforum lists all the coastal alternatives that I found. Each one of these is IMO a million times more beautiful than the camino alternative.
7. Time to allow -- I would look at the number of days on gronze, mundicamino and eroski, and get an average and then add a few for padding.
Hope this helps, Jeri. Buen camino, Laurie