Yes, usually, but not nessesary. As mentioned before most modern “matched” pickup sets have a “hotter” bridge pickup. The reason behind this is that the movement of the strings (the amplitude) are bigger in the neck position compared to the bridge and the electrical output of the pickups if they where made identical would be higher from the neck pickup. The other reason for making a neck pickup with less windings are that this by itself is changing the tonality of the pickup, thus also matching the tone of the pickus closer to each other (not just output). On the other hand SRVs famous no1 allegedly had the hottest pickup in the neck position…
With perfectly matched bobbins you will get one sound. With an offset between them you will get another sound. Me, I like slightly offset pickups in the bridge position and more offset pickups in the neck position. I feel taht it opens up the sound and makes it "airy". Some like the pickups to have as closely matched coils as possible. You can have an offset in the 10-15% range without loosing too much of the hum canceling effect
The most recognized difference between alnico and ceramics are in magnet strength. Magnets used for guitar pickups (and other applications too…) are graded in simple numbers Alnico 5 are stronger than Alnico 2. Ceramic magnets are usually graded C8. The most significant difference is that a stronger magnet makes the pickup produce more current (higher output/hotter). But that is not the only difference. The real trick is to figure out how each grade and each material affect the sound and how you can use that knowledge to tailor a pickup to a specific sound. Learn to explore what difference an Alnico 2 magnet make to a pickup with Alnico 5 magnets. Then try a ceramic, or Alnico3, 4, 6 or 8 magnet. When you have got a basic understanding of those differences it is time for us to discuss the subtle differences between different pickup wires, different winding techniques, different screw, slugs, keeper bars, base plates and covers. And maybe discuss if a pickup sound different with plain ole ABS for bobbins or using the legendary historic correct butyrate for bobbins…